Ancient Middle East: Explore the Hidden Wonders of Jordan and Iran with Christopher Clark

I'm Christopher Clarke and I'm traveling the world to discover its true treasures, the UNESCO World Heritage Sites. This time I'm in the Middle East with its relics of long-lost global empires, its palaces, mosques and legendary squares. My journey will take me to Isfahan, to Persepolis, Tehran and Yazd in Iran. But first I'm headed to Jordan, into the desert of Wadi Rum and to the old Nabataean city of Petra carved into the cliffs. Wadi Rum is breathtakingly beautiful and it's much more than just a desert. A spectacle of stone, sand, light in a time that seems to stand still. This is the landscape of Wadi Rum. For 12,000 years the Bedouins in their culture have occupied this place. And what remains today of that long history? That's what I'd like to find out. These desert cliffs are up to 400 meters high. The Arabs call them Hizmah. When the sandstorms come it feels like you're on another planet. This valley was created by a geological fault more than 30 million years ago. Even the stars bowed down to this land with us, as the Bedouins say. They revere this region. It has been their home since time immemorial and it's a world heritage site. They live in tents that they weave themselves from goat's wool and camel hair. I am a guest of the Bedouin Sheikh, the chieftain of the tribe. The sound of the coffee mortar is an invitation. Coffee is more than a drink to the Bedouins. It came to them on the caravans from Yemen, where the Sufis used it to keep themselves alert during their night-time devotions. There's an entire ceremonial culture associated with coffee. This is Sheikh Abu Nasr, the chieftain of the tribe, and his brother, who was also his deputy. How long has this tradition existed? We've been brewing coffee for thousands of years. It's an important legacy from our ancestors. You will find coffee in every household. Drinking it is a valuable ritual for us. Coffee is more than just a symbol of hospitality. Business deals, negotiations, problem-solving — nothing happens without coffee, even within the family. You drink three cups, the first for your soul, the second for your sword, and the third because you are a guest. This is where the nomadic tribes who passed through this region 3,500 years ago depicted their world — themselves, of course, as hunters, but also the domesticated animals, without which life in this part of the world would have been impossible. And we see here not just images, but also letters — letters from the third century before Christ, a reminder that literary culture, the culture of writing, has a long tradition in this place. I am meeting with the Bedouin Ali Muhammad, who is explaining the importance of this cultural site to me and upholding the legacy of his ancestors. Ali, thank you for coming. My pleasure, thank you. People use this route for camel caravans between Hejaz and Arambia and the Mediterranean Sea. The caravans travel through our region, Bari Rum. This spot here was a campground. The images and writings point to the coast. Goods were traded here. Leather from Arabia might be exchanged for silk or textiles from India or China, for example. Ali, are you personally proud to be able to call these people your ancestors? Yes, I'm very proud. We are Bedouins. We own camels. We used to transport all the goods in our caravans. Now we have settled in Bari Rum and are very proud of our ancestry. When British agent Thomas Edward Lawrence, known as Lawrence of Arabia, was travelling in Bari Rum, he said that he felt humbled into insignificance by this landscape. And that makes sense to me. And I find it difficult to leave this magical place. But my destination is something of a consolation. I'm on my way to Petra, the millennia-old city carved into the cliffs at what was once the heart of an ancient Middle Eastern network of trade routes. The Nabataean people lived here. Petra was their capital, with palaces, temples and tombs once lining a processional route. Relics of a great past, a civilization that, despite extensive research, is still shrouded in mystery. The city can only be entered from one side. At its narrowest point, the path is only two metres wide. This narrow access route made Petra impregnable, and some descendants of this legendary people still live here. The Nabataeans, people who carved this area here, they start carving the area and the temples in the area here. It's our grand-grandfather they carved that, and they were Nabataeans, originally Nabataeans, they come from Yemen to Petra, and to have this area as a capital for them, and that is in 5th or 6th century BC, they do this. It was very famous at the olden time, because at the olden time, in 5th century BC, there were about 20,000 people of Nabataeans, they were living here and they have their palaces and they have their kings, especially like Aretas I and II and III and IV, and they were the kings of the Nabataeans. The Nabataeans came to the Transjordan region in the 1st century BC. Their caravan raids were widely feared. Later they hit upon a more lucrative business idea and began serving as escorts to caravans en route to the Mediterranean. They also started trading. Isn't there something a little surreal or even absurd about the fact that there's an enormous city carved into the rock in the middle of a desert? Petra grew into a metropolis because it was located directly along one of the world's oldest trade routes, the Incense Road. Incense, myrrh and spices like saffron, pepper and cinnamon. Back then, all of these items were as valuable as gold and they stimulated a flourishing international trade. The Nabataeans, who were a bit like the oil sheiks of the 20th century, transported this precious cargo from the Arabian Peninsula through the desert to the Mediterranean Sea via countless camel caravans. It was a sort of living pipeline. For a long time, it was believed that the Nabataeans had left behind a golden treasure trove in Al Khazneh, the treasury hidden deep in the cliffs. The rumour is what lent this place its name. But the treasure was never found and now we know that in fact this was a mausoleum for a Nabataean royal family. The elaborate façade tells a story of the power of this people who conquered more and more territory. At the pinnacle of their power, the Nabataeans even conquered Damascus and laid siege to Jerusalem. But they'd clearly pushed their luck. The Roman Empire was having none of it and summarily annexed their territory. The Nabataeans became Roman vassals. The kingdom became the Roman province of Petraea. But why did this formerly flourishing mercantile city ultimately fade? In the third century, mercantile cities like Palmyra in Syria rose up as competitors. And on top of that, Petra was hit by multiple earthquakes. No one knows exactly why the city was abandoned, but we are learning more and more about the architecture of this place, which is being explored on behalf of UNESCO by archaeologists like Giorgia Cesaro. The style was very much influenced by the Hellenistic style coming from Greece. In fact, the Nabataeans were merchants, so they were trading with the Greeks at the time, and they imported also some of their architectural styles. So, of course, there were also local features. For instance, the Nabataean capital is peculiar, it's typical Nabataean, and it can be seen at the main monuments like the monastery or there or in the treasury. Today, Petra is mainly under threat from the large volumes of water that collect in the recesses of the cliff face during heavy rain. The water continuously hollows out the structures and can lead to avalanches. The Nabataeans knew how to handle these risks. Water needs to be managed appropriately, and Nabataeans knew how to do that, and they were incredible engineers, hydraulic engineers, so they were able to divert waters in order to prevent floods in the site, but also to manage water for living uses and to store water again for the house and to live. And all these features are visible today, and if we could reactivate all of these, we could probably reduce the risk of floods at the site. A large-scale UNESCO program involving a team of geologists has been set up to protect the Petra sites from earthquakes and from enormous chunks of falling rock. Experts are training locals from the surrounding wadis. They can help the missions to protect this World Heritage Site, for which they feel an almost proprietorial responsibility. The knowledge of the Nabataeans, who were expert engineers, is now being put back into practice here. We have, see here, the channels. We need repair or restoration of the channels for the water, because some water go from up there to the wall to make some damage to save this structure, to make a control plan and management to the water. Fantastic, thank you very much. And this is also how they search for loose pieces of rock that are on the verge of falling and causing damage during the next storm. Thanks to these special techniques, loose rocks can be encased and secured. It will take many years to complete this work, but in the end it will help to preserve this World Heritage Site for generations to come. This is a human creation, but it looks as though it grew naturally from stone. Architecture in elegant synergy with the physical environment. Jordan is a land of many wonders. I'm headed into the desert east of Amman, which is home to this gem, Qusayr Amra, built in the 8th century AD. Caliph al-Walid ibn Yazid of the powerful Umayyad dynasty commissioned the construction of this little pleasure palace. But why here, of all places, in the middle of a desert, where at most you could expect to have a few Bedouin families as neighbors? In the Middle Ages, the German Kaisers traveled from Palatinate to Palatinate, and the Caliphs of the Arab world did much the same. They would relocate their entire court along with them every time they had to travel in order to demonstrate their power to the various Bedouin tribes within their often enormously extensive territories. This lovely spot, a little desert palace, is only about the size of an average three-room apartment, about 80 square meters. But a whole universe was contained within this space, the world of the Umayyads, the first powerful rulers in the history of Islam. The frescoes in this treasure chamber are unique. They were painted into the fresh plaster. The images depict the joyful, hedonistic quality of life at an early Islamic court. You may be asking yourself, doesn't Islam strictly forbid the visual depiction of living beings? Well, it's true that today many Muslims believe that since God is the sole creator, no artist has the right to imitate that original act of creation. Whether this injunction can really be unambiguously derived from the Quran is debatable. By the time the prohibition of images started to come into effect in the late 8th century, the sumptuous festivities at the court of Caliph al-Walid II were a thing of the past. As for what went on in this bathhouse back then, I'll leave that up to your imagination. These frescoes offer extraordinary insights into early Islamic art. One inscription reads, may Allah make al-Walid ibn Yazid virtuous. Perhaps there was a reason for that. In any case, it's clear that al-Walid had his pleasure palace built when he was still a prince, and he definitely made use of it. Archaeologist Romail Ghareeb knows this place better than anyone. This place is a special place. It's not for public. It's only for the caliph who was, you know, who's ruling this area, the capital in Damascus. They are coming down here to the desert to get sometimes fun, to get hunting, get relations with Bedouins or tribes who was living all over here. So this is a very private site. There is some images which you can read from this, that this is a Christian site, especially when you look at the images of Jesus or the ancients' images. But also this is very simple to say that people who was living here, artists, they are doing the same images in the churches, which in Jerusalem, in Damascus, in Amman, all over this. So they are the same artists who are doing this kind of fresco. For years, the frescoes underwent restoration using special techniques. But already in the 19th century, an incredible discovery had been made. Among the figures depicted here are the emperor of China, Roderick of Spain, the king of the Goths, and the king of Ethiopia. The caliph apparently considered these rulers as his peers. But pride comes before a fall. Al-Walid's reign lasted for just one year, after which he was overthrown and assassinated. And that marked the beginning of the end for the Umayyad dynasty. This desert palace was abandoned forever. It remained as a witness to an ancient heritage, preserved here as though it were locked away in a vault. I'm on my way to visit what remains of the hub of one of the great civilizations of the ancient Middle East. Long before there were great empires in Europe, Persian king Darius founded the ceremonial capital city of his empire in 520 BC, Persepolis. He found the perfect location in Persia's mountainous south. The old Persians called it Parsar. Persepolis was its Greek name. Little remains of its palaces and temples on this rocky 15 hectare plateau, but you sense that this was once the headquarters of an imperial power. Even the ruins are awe inspiring. And this is how Persepolis looked in Darius's day. In the center was the Apadana, the king's audience hall. His residence was next to that, as were smaller palaces for the members of the royal court. The decisions made in this place had a lasting impact on the history of the world. The Persian empire continued to expand, subjugating growing numbers of people. Conquered peoples sent envoys to Persepolis once a year, and they were always warmly received. King Darius and his successors were not arrogant in victory. The delegation sent by the 28 conquered nations entered the city of Persepolis through this gate of all nations. The Persian empire was the largest the world had ever seen up until that point. Around 500 years before Christ, the empire comprised 44% of the global population at the time, and it extended from Egypt in the west through Turkey and all the way to Afghanistan and Pakistan in the east. The gate of all nations was an advertisement of the empire's pretensions. It opened like a large friendly moor to accept the envoys of other nations that were now a part of the greater Persian empire. Once they passed the gate, they were permitted to climb the stairs to the audience hall, just like the Persian nobles. On the day of the Persian new year, Nowruz, delegations from all 28 countries climbed these steps up to the palace to pay tribute to the king. We can still picture it now as though we were watching a film. The Arabs with a camel, the Carians or Serangians with weapons and a cow, the Libyans with a goat and cart, the Ethiopians with a jug and ivory. All of them came here to honor the king of kings. At the eastern stairs of the Upadana palace, you can still make out the courtiers and the incredibly detailed reliefs. They're over 2,500 years old. Some archaeologists believe that the emperor invited Greek artists to create these depictions. The differences between the delegations and their cultures are clearly visible. These images show only harmony and peace. There are no representations of strife or war. To be immortalized in a relief in this most sacred of places was considered an honor naturally, but it was also a clear declaration, set in stone literally, that these peoples owed the Persian king their undying obedience and service. All delegations had to report to the ruler. This was how he held together an empire made up by such diverse parts of the ancient world, and the monumental Upadana was the place where they all came together, the center of the king's empire. This was the seat of imperial rule, and in the conquered territories, governors known as satraps were installed. Just like the Romans a thousand years later, you might be thinking, but there is one important difference here. The Roman emperors wanted their subjects to identify with Rome, to become Roman. The Persians too were absolute rulers. They referred to themselves as Shahanshah, or king of kings, but unlike the Romans, they permitted diverse religions and cultures in their empire. In fact, they were proud of that diversity. Naturally, they ruled with an iron fist, but that iron fist was wearing kid gloves, so to speak. In October 1971, the Shah at the time, Reza Pahlavi, celebrated the 2500th anniversary of the Persian monarchy in Persepolis. He invited monarchs and presidents from around the world to the grandiose festivities, as though he were pretending to be Darius I. Everybody had an active role in Achaemenid culture. No nation was dead during the Achaemenid period. It appears that everyone was in constant interaction and cultural exchange. If we were to pinpoint the major foundations that helped the formation of this civilization, it appears that the relative freedom established at that time facilitated all those interactions and cooperations. Therefore, each culture was given the chance to show what it had to offer. In that sense, the Great Audience Hall and its columns are still an important part of many Iranians' identity, despite or perhaps because of the fact that they represent a time before Islam had come to this country. This is another reason why, after the Islamic Revolution in 1979, the Ayatollahs wanted to tear out the last roots of the monarchy and finally raise Persepolis to the ground, but they were prevented from doing so. UNESCO named Persepolis a World Heritage Site in the same year, and the Iranians' pride helped to preserve this place. Of course, the Persians weren't merely kind-hearted philanthropists. If they had been, they wouldn't have waged bloody wars or conquered so many nations. But when Cyrus the Great took Babylon, he did something that no conqueror before him had ever attempted. He refused to create a regime of fear or to enslave his new subjects. He tolerated all their customs, traditions, and languages. And he freed the Jews from Babylonian captivity and ensured that they could return to Jerusalem and rebuild their ruined temples. With this act, Cyrus the Great earned himself a place in the Old Testament of the Bible. And it was in Babylon, too, that a more than 2,000-year-old object was discovered which, at first glance, looks like a terracotta rugby ball. But the engravings on this object, known as the Cyrus Cylinder, are actually something like the first charter of human rights. The Cylinder has been compared to the English Magna Carta or the American Constitution. The Cylinder reads, I declare today that every person is free to practice any religion they desire and to live where they please on the condition that they do not infringe on the property of others. Some tombs of the kings of Persia are carved deeply into the rock, but sadly it seems as if they've taken with them the idea of tolerance and respect for other cultures and beliefs. There are, of course, many downsides to empires. They're forged in war and they rule by force. But in order to survive, an empire also has to secure the allegiance of many peoples representing more than one ethnicity, language, and religion. Persepolis continues to act as a reminder of one of the most powerful world empires, and it's a source of pride for Iranians who remember that their country once hosted this most civil of ancient civilizations. A civilization whose descendants extended into the modern era. Here in Persepolis, you find inscriptions all over the ancient ruins, and they stem from different historical periods. This one is 1,700 years old. It comes from the Sassanid era, and it marks the visit by one of the satraps of the shah, a certain Shahpur, the visit that he made to Persepolis about 1,700 years ago. And of course he's wanted, with this inscription, he's sought to connect his name with the prestige and the value of this place. And here, on the other hand, we have an inscription from the 19th century, from the year 1876 to be precise, when the ruler of that time, Nasreddin Shah, came to Persepolis. And this inscription marks his visit. But what's interesting about this particular inscription is that in 1979, at the time of the Islamic revolution, the name of that ruler, Nasreddin Shah, was removed. It's been chiseled away by a supporter of the revolution. And over here, the same has happened with the formula Shahanshah, king of kings, because after that revolution, this figure in particular, Nasreddin Shah, had become an unperson. He was no longer wanted. The memory of him was to be erased. He was irrelevant. And then, in the middle of the First World War, Sergeant Lucas of the 21st Lancers inscribes his way into world history with this very simple piece of graffiti. It's the presence in one place of all these layers of time that's so fascinating. It almost makes you dizzy. The glories of Persepolis were already a thing of the past when Alexander the Great defeated the armies of Darius III in 331 BC. Alexander marched into Persia and committed a supreme act of vandalism when he entered Persepolis and put the city's magnificent buildings to the torch. It's widely believed that he did so as revenge for the partial destruction of the Acropolis in Athens by the Persians. In the 18th century, Tehran, in the north of the country, became the capital and the Shah's place of residence. The official seat of the monarchy was Golestan Palace, with its extensive gardens. At first glance, it seems as though this place is a celebration of the ancient Middle East. But a new era was beginning. Soon the country would no longer be called Persia, but Iran, the land of the Aryans, a master race. It was a message to the rest of the world, to which Iran was increasingly turning its attention. For 2,500 years, the mixing of diverse cultures was a key feature of the Persian Empire in its various iterations. And then in 1848, when Shah Nasruddin ascended the throne, a new element was added, Western culture. The Shah was an enthusiastic traveller to Western Europe, and he was determined to implant its culture in his Persian homeland. Persian influences were pushed into the background, and the Golestan Palace in Tehran is a fascinating symbol of a process of cultural change that would come to a tragic end in the 20th century. The tens of thousands of mirrors endow this UNESCO World Heritage Site with an oriental mystique. But the architectural style was conceived in imitation of English and French palaces. This palace is a synthesis of everything the builders had seen on their many trips through Europe. Alienated from their own traditions, they wanted to play cultural catch-up. English paintings and French porcelain were essential. We're in the throne room where in 1967, Shah Reza Pahlavi crowned himself emperor, and his wife Farah the first empress in Persian history. In so doing, she later said, he made all women in Iran empresses. The monarch, a determined and authoritarian ruler, initiated reforms that did not sit well with the deeply religious members of his society. Islam was also undergoing a process of revival and intensification in the country, and many Iranians felt that the Shah's interest in the West represented a threat to their values. This process had already begun under the Shah's father, who was also named Reza, and resided in these rooms. I can't help wondering what pious Muslims made of images like this. For example, And then came the revolution in 1979. Many groups supported the revolution, but it was the religious who came to dominate the new regime. The Shah and his family fled the country, and Ayatollah Khomeini transformed Iran into a strict theocracy. Persia had once absorbed Islam, Persianizing it. Now Islam absorbed Iran. The imam's name and image are still omnipresent in the Islamic Republic. The square in front of the Jame Mosque in Isfahan was renamed after Khomeini. The city's ancient tradition was folded into the new normality of clerical rule, but history can never be completely erased. When French traveler Jean Chardin arrived in Persia in 1666, he wrote that he found himself in the happiest and most flourishing empire in the world. A magical place full of luxury, and yet so much more than a mere eastern fantasy. Isfahan was located on the Silk Road, and the Persians traded with India, China, Central Asia, and Byzantium. This was essentially the world's first common market. The carefully constructed network of roads was the perfect complement to the ports of the Persian Gulf, and alongside Constantinople and Cairo, Isfahan became one of the world's most advanced metropolitan cities in the 17th century, with bridges and bazaars, with gardens and palaces. The heart of Isfahan is a square, and not just any square. It's said to be the largest in the world, the length of five football fields. This UNESCO World Heritage site tells the story of the city's golden age. It began when Shah Abbas I named Isfahan his capital in 1598. He summoned architects and artists from every corner of the empire, an empire that was already more than 2,000 years old. There was plenty of material to work with. He wasn't exactly starting from scratch. From this spacious, airy terrace, Shah Abbas could survey his entire city of paradise. He called this expansive square in the city centre the image of the world. Just opposite was his private house of prayer, to the right was the enormous royal mosque, and to the left the gate of the bazaar that he loved to visit on his own, without bodyguards. Isfahan was a safe place back then. The city didn't even have a prison. Abbas I succeeded in establishing Isfahan as a global centre for art, handicrafts, science and trade. And this is the Shah, surrounded by his royal court. No one before or after him has been so passionately revered in this country. Iranians still come to admire the enormous paintings in his garden palace. And the people of Isfahan are still proud of what was created under his rule. The rich artisanal traditions are alive and well here at the bazaar. Shah Abbas loved to chat with people. He would look over the artisans' shoulders as they worked, carpet makers, textile printers, glass blowers, and especially metal workers. In the late 2nd and early 1st millennium BC, the art of metal working was already flourishing in Persia. This technique is known as Ghalamzani, the art of engraving elaborate reliefs in silver, copper or brass plates. Almost all of these objects have very elaborate patterns on them. Are these patterns, do they have a meaning or are they just decoration? Oh no, these are ancient Persepolis patterns. This here, for example, is an old Persian king. Darius? Yes, and these are his soldiers and the deity Ahura Mazda. Isfahan is a center of metal work and of engraving but also of many other handicrafts. Why is this city such an important center for handicrafts? How did it become that way? Because since ancient times, Isfahan has been the home of great Iranian kings. The main road connecting different parts of the world passed through Isfahan and it was a center of trade. Merchants from all over the world came to Isfahan. All sorts of handicrafts and other things could be found in Isfahan. This is how Isfahan became a cosmopolitan city. Shah Abbas also commissioned the construction of this bridge. People from other cultures crossed it to enter the city. Muslims, Jews, Zoroastrians, Christians and people of other faiths managed to live peacefully side by side in this place. Even today, Isfahan still radiates tolerance and a zest for life. In Abbas's day, the bazaar represented trade, the palace sovereignty and the mosque religion. Today, the 11th century Jame Mosque is also a UNESCO World Heritage Site. It is the mother of all mosques in Iran and the largest one in the country. Every leader over the centuries expanded it further, added more to it to honor Allah. The result is breathtaking. The Shah, who incidentally was born in the same year as astronomer Johannes Kepler and painter Caravaggio, invited craftsmen and artists from around the world to Isfahan. They brought cobalt and indigo pigments from India and China using a secret kilning process to create the perfect blue that we see in the tin-glazed pottery and mosaics. Quran verses are harmoniously interwoven with patterns from nature. The Quran views nature as a book in which God reveals himself to humanity. This is another reason why gardens play such a vital role in Persian culture. The most important design elements include effects of light and shadow that highlight plants, pavilions and masonry. Gardens were so important to Persian culture that the old Persian term paridaida, which was synonym for garden, became the word for paradise in many other languages. The Persians essentially invented the enclosed structured garden and its elements influenced countless other cultures. It all goes back to Cyrus the Great, who had a garden planted around all of his palaces in the 6th century BC. They were ornate private oases but also symbols of his power and greatness. Persian gardens are part of UNESCO's world heritage. Even Marco Polo described them as a paradise where the best fruits in the world grew and where the canals that ran through them flowed with milk, honey, wine and water. While I couldn't find the canals Marco Polo mentions, like many Europeans of the time, the Venetian trader bigged up his reports of the Orient with fantastical inventions. Today our image of the Middle East is shaped more by media reports of extremism, political tyranny and mass migration. And particularly in this age of deepening alienation, UNESCO world heritage is all the more important. It reminds us not of what divides us, but of what unites us. In his West Eastern Divan, inspired by the Persian poet Hafez, the German writer Johann Wolfgang von Goethe finds words that still feel fresh after 200 years. If you truly know yourself and you know another's heart, then you'll know that East and West cannot be pulled apart. I'm on my way to the remote city of Yazd in the barren heart of the country. Approximately one-sixth of Iran is desert and the Iranian deserts are legendary, the hottest and most arid areas of the country. There's very little humidity, rain is rare, the weather is extremely hot in summer and cold and dry in winter. But there's a lot of beauty in these desert regions. Some areas are dominated by dunes, the deserts of Central Asia and the subcontinent are mostly sand covered. But the largest impassable area lies on the Iranian plateau in southeastern Persia. Yazd's location in the middle of a desert protected it from wars for thousands of years. When Genghis Khan's hordes descended on Persia, artists and philosophers sought refuge here. The traditional structure and design of this earthen city earned it a place in the list of World Heritage Sites. The city of Yazd is located in the Vavghe desert, close to the ancient spice and silk roads. The people here found ingenious ways of making do with the scarce resources available in a desert region. Water flows into the city through a sophisticated system of pipes and channels. Modernization has so far spared this remarkable city. This city will truly make you feel as if you've traveled back in time. Founded next to an oasis nearly 3,000 years ago, Yazd is one of the oldest continuously inhabited cities in the world. Its architecture is perfectly adapted to the hot climate here in the middle of the desert. Even today, many buildings are constructed using clay bricks. And the city's residents still benefit from the ancient wind towers constructed on top of residential homes and above cisterns. In fact, they are part of a centuries-old air conditioning system. It's a very clever design and I want to take a closer look. The landmark wind towers jut out above the city, shaping the skyline. It's really hot outside, 36 degrees in the shade, but here it's pleasantly cool. Why? Because of water and wind. This structure is basically a gigantic architectural heat exchanger. Cool air comes down through the tower, it's further cooled by contact with the surface of the water, and the warm air inside the house, pulled up by a thermal current, leaves the house through this half of the tower. It works like this. The water required for this system comes from the high mountains nearby. Deep below the Jume Mosque of Yazd is the entrance to a system of channels that was constructed back in the 5th century and provides the city's water supply. It's a technological masterpiece. A whole network of these channels, known as qanats, extends like a spider web from Yazd into the surrounding country. This system also became the standard in other parts of Iran very early on. It, too, belongs to the UNESCO World Heritage. The water is collected in qanats outside the city of Yazd, close to the nearby mountains, where the rain tends to fall. The qanat system performs with amazing consistency. There are only small variations in flow from year to year. In this dry region, a regular supply of water is an almost miraculous achievement. Yazd is on the UNESCO World Heritage list because the city and its surroundings are an outstanding example of a traditional settlement. It represents the interaction of humans and nature in a desert environment, and most of all, it is still intact architecturally and culturally. Today, Yazd remains an important center of a religion that emerged nearly 3,000 years ago and is said to have been founded by Zahra Fustra, a Persian poet and philosopher. There's some debate as to whether or not he actually existed at all, but the teachings of the Zoroastrian religion still survive today. They focus on the battle between good and evil, between light and darkness. It's said that good will triumph over evil on Judgment Day. Until then, people can make conscious decisions to follow the right path, the path of truth. There are three maxims in Zoroastrianism, good thoughts, good words, and good deeds. Mozart picks up on these themes in his most famous opera, The Magic Flute, when Zoroastro sings, It's said that Zahra Fustra guards a flame in the Zoroastrian temple that has burned continuously for 1,550 years as a symbol of light and goodness. In addition to the temples, the country is dotted with dachma, or towers of silence, the most striking architectural evidence of Zoroastrian belief. One commandment of Zoroastrianism dictates that the earth be kept pure. So, in order not to pollute the ground, the bodies of the dead were kept in these towers of silence outside the city. In these stone circles, their remains were left to the elements, and to the birds of prey, who picked the flesh clean off their bones. The towers remained in operation into the 1970s, when the practice was ultimately banned, for hygienic reasons, as the authorities put it. But the Zoroastrian faith lives on in Iran. As I leave this remarkable country, I recall the line of a poem by Rumi, the celebrated 13th century Persian poet. Far out, beyond our notions of orthodoxy and error in religion, there is a field, I'll meet you there. When the soul lies down in that grass, the world is too full for words. Here was a Muslim poet proposing that the foundation of faith lay not in a specific religious code, but in the compassion and love between humans. It sounds radical today. Rumi came up with it 700 years ago. For modern Europeans, the Middle East is both a politically contested region and a fantasy of sensuality and opulence. What we actually find here are the relics of great nations and civilizations, and political cultures united and divided by religion. The UNESCO World Heritage Sites are interesting because they show us what has stood the test of time. Places recalling a world of diversity and sometimes of tolerance. Places of memory, but also, maybe, points of departure for a better future.