Tulum was one of the last cities built and inhabited by the Mayans, serving as a major trade hub for Coba, it was at its height between the 13th and 15th centuries and managed to survive about 70 years after the Spanish began occupying Mexico. Go snorkeling in the lagoon of Yalkoo, a former natural Mayan harbor and caved in cave system. Tulum was a walled city, protected on one side by steep cliffs facing the sea and on the other by a wall of about 12 feet in height. Tulum served as a trading port. The ancient Maya name was ZAMA=City of Dawn or City of the Morning Star. The buildings that are visible on the site date from the Post-Classic period, around 1200 to 1500 A.D., and the city of Tulum was functioning at the time of the arrival of the Spaniards.