Sediments drawn from the Blue Hole and other sites in Belize suggest that the Mayan civilization may have collapsed twice due to drought.
Mind-altering substances were all the rage 1,500 years ago, at least among certain elite members of a South American society.
One of the cities featured an extraordinary facade with an entrance representing the open jaws of an earth monster.
No other site has so far been located in this area, which extends over some 1800 square miles in the Mexican jungle.
Failed monsoons in 14th and 15th century coincide with the Khmer Empire's collapse in SE Asia.
Are pit bulls as dangerous as Maryland thinks they are? How long should women breast-feed? Did the Mayans actually predict doomsday? Find out the answers in This Week in Discovery News.
Check out The Hunt for Lost Cities: Photos