Each Mayan city had a specific purpose, and Tulum was no exception. It was a seaport, trading mainly in turquoise and jade.

As well as being the only Mayan city built on a coast, Tulum was one of the few protected by a wall.

Made of limestone, the 784-metre wall encloses the site on three sides, is seven metres thick, and varies between three and five metres in height. No doubt this fortification helped preserve the seaport.

Like the questions which surround the decline of the Mayan world, there are several theories as to why a wall surrounds Tulum. One has a Mayan population of 600 on the inside, protected from invaders. Another suggests only priests and nobility were housed within the walls, while peasants were kept on the outside.