Tulum was one of the last cities to be built by the Mayas and served as an important port for the major city of Coba situated 45km inland. It reached its peak between 1200-1500 AD and managed to survive about 70 years after the Spanish colonisation, before diseases brought by the invaders caused its collapse and abandonment by 1600 AD. Tulum consisted of a series of small palaces and temples defended by a high stone perimeter wall, 380m north to south, and 170m east to west, with the eastern boundary being the 12m high cliffs overlooking the Caribbean Sea. The largest structure is El Castillo, a spectacular cliff-top temple. Originally these stone buildings would have been covered in plaster and painted in reds, blues and yellows. Tulum had an estimated population of 1,000 - 1,600 inhabitants, most of whom would have lived outside the perimeter wall in wood and thatch buildings.