Tulum, 130 km south of Cancún, is at first sight the most beautiful of the Mayan sites, small, but exquisitely poised on the fifteen-meter-high cliffs above the Caribbean. 

When the Spanish first set eyes on the the place in 1518, they considered it as large and beautiful a city as Seville, Spain. They were, perhaps, misled by their dreams of El dorado, by the glory of its position, and by the brightly painted facades of the buildings, for architecturally Tulum is no match for the great cities. Nevertheless, thanks to the setting, it sticks to the memory as no other.

The site (open daily from 8am-5pm) is about one km from the main road, so be sure to get off the bus at the turnoff to the ruins and not at the village of Tulum a few kilometers farther on. You enter through a breach in the wall which protected the city on three sides-the fourth was defended by the sea. This wall, some 5m (16ft) high with a walkway around the top, may have been defensive, but more likely its prime purpose was to distinguish the ceremonial and administrative zone (the site you see now) from the residential enclaves, which were mostly constructed of perishable material.

As you go through the walls the chief structures lie directly ahead of you, with The Castillo (the castle) rising on its rocky prominence above the sea.

At The Templo de los Frescos (temple of the frescoes) the partly restored murals that can be seen inside the temple depict Mayan gods
 

And symbols of nature's fertility: rain, corn and fish. They originally adorned an earlier structure and have been preserved by the construction around them of a gallery and still later (during the fifteenth century) by the addition of a second temple above it with walls which, characteristically, slope outwards at the top. On the corners of the gallery are carved masks of Chac, or perhaps of the creator god Itzamna.

The Castillo, on the highest part of the site, commands imposing views in every direction. Aside from its role as a temple, it may well have served as a beacon or lighthouse; even with out a light it would have been and important landmark for mariners along an otherwise monotonously featureless coastline. You climb first to a small square, in the middle of which stood an altar, before tacking the broad stairway to the top of the castle itself. To the left of this plaza stands the Templo del Dios Descendente. 

The diving or descending god-depicted here above the narrow entrance of the temple-appears all over Tulum as a small, upside-down figure. His exact significance is not known; he may represent the setting sun, rain, or lightning, or he may be the bee god, since honey was one of the Mayan's most important exports. Opposite is the Templo de Las Series Iniciales (temple of the initial series), so called because in it was found a stela bearing a date well before the foundation of the city, and presumably brought here from else where.

Further interesting places to explore are strung out south along the coast.

If you simply want to take time out for a swim, you can plunge into the Caribbean straight from the beach fronting the site.