#乌纱帽奇怪的冷知识： https://www.youtube.com/watch?v=5gXJ5f3PzfI&list=PL3oLcVVpWzNcU-nwygZLS02vcdkcXCIC2各国历史合集： https://www.youtube.com/watch?v=G7KFSu9hJHw&list=PL3oLcVVpWzNeP9rsN4zIEreApSLgdxwdY
