Scientists are learning from the 1700-year-old Lycurgus Cup, which changes colour thanks to nano particles.
				0
			
			The exact cause of death and burial site of Genghis Khan is unknown, because all of the 2000 funeral guests and 800 soldiers were killed in order to preserve the secret.
				16
			
			Genghis Khan exempted the poor and clergy from taxes, encouraged literacy, and established free religion, leading many peoples to join his empire before they were even conquered.
				28
			
			During the Black Plague, it was thought that bad smells were the cause of the plague. "Plague Doctors" therefore wore masks with long beak-like noses stuffed with flowers or smoke to hide the smells.
				19
			
			Modern humans first appeared about 200,000 years ago, but record keeping didn't begin until about 6,000 years ago. That means about 97% of human history is lost.
				21
			
			

