What are some fascinating things about Genghis Khan and the Mongol Empire?

This is NOT a homework question or anything academic related. I am simply somebody who fell in love with history with great fascination and curiousity. I've read about Julius Caesar, Alexander the Great, Napoleon Bonaparte and Augustus Caesar...As well as the Roman Empire, Persian Empire and Ottoman Empire... But Genghis Khan (and his later generals and rulers) and the Mongol Empire, in my opinion, was quite something else and were on a very different level...