Mongols were allegedly cannibals, drinking human blood and eating human flesh.

The Mongols viewed artisans as important and would spare them.

However, they killed millions in order to obtain their empire in the first place.

Estimated to have killed several million people throughout their conquests.

The Mongols spread the plague through their travels, as well as allegedly hurled plague-infected bodies at their enemies.

During the Siege of Bukhara, around a thousand soldiers that didn't want to surrender to the Mongols took refuge in a mosque, thinking that the Mongols wouldn't kill them. However, they were wrong and the Mongols shot flaming arrows into the mosque and even allegedly hurled burning oil on catapults at it.

The Mongols practiced religious tolerance throughout their empire.

The Mongols increased communication throughout Eurasia and reopened the Silk Road, which allowed for goods, ideas, cuisine, etc., to be spread throughout the continents again.

As Genghis Khan attacked Bukhara, he reportedly entered a mosque and and emptied cases that contained Qurans, then filled them up with grain for his horses. As he left, he said, "I am the punishment of God. If you had not committed great sins, God would not have sent a punishment like me on you."

In 1220, Genghis Khan leveled the city of Balkh Bukhara. Even in 1330--over a hundred years later--the city was described to still be in ruins as a result of the brutality and destruction from the Mongols.