Terpen: The Massive Hand-Built Mounds That Saved a Culture

For over a thousand years before the invention of sea dikes, coastal communities along the North Sea survived in a dynamic intertidal landscape by building massive artificial earth mounds known as terpen or wierden. Situated across the modern salt marshes of Friesland and Groningen in the northern Netherlands, these hand-built hills provided the only permanent dry ground during regular tidal floods and devastating storm surges.