38. The Library of Alexandria, Egypt

This may be one of the oldest lost sites on the list, and to many of us history and knowledge nerds, the biggest tragedy of all. The Library of Alexandria was the biggest library of its time, a universal Athenaeum of papyrus scrolls that had an estimated number of 40,000 to 400,000. It became known as the capital of knowledge and learning.

Contrary to popular belief, experts say it was not destroyed by a fire but gradually declined until its final destruction in 275 CE, if there was anything left to it. Still a shame all that knowledge may be gone, but on the bright side, the ruins can still be seen to this day!