What moment overthrew your understanding of history?

1908, Russian kozlov opened the door of a mysterious dynasty in Heishui, northwest China, which was simply an underground library buried for 800 years. Strange figures, exquisite Buddha statues, gorgeous paintings, and countless ancient books and documents. In St Petersburg, Russian, sinologists found that these documents came from a dynasty called Xixia in ancient China. Behind these documents is a mysterious civilization, a lost civilization.