On the caribbean cost of the Yucatan lies Tulum, a seaside Mayan site. Tulum is relatively barren, there are no towering pyramids or expansive ball courts, but Tulum has the sea. Built above the strikingly blue waters of the caribbean, Tulum must have the best view of any ruins. It was used a fortress and has a number of buildings which the first explorers would have seen as they viewed Tulum from a distance, unable to anchor nearby due to the mesoamerican reef, which spans from Mexico to Belize, making the second largest reef system in the world. Today the site if one of the most popular in Mexico due to its proximity to Cancun and Playa Del Carmen.
There are about 3,000 cenotes in Mexico, which are limestone sinkholes filled with water. The cenotes are largely connected by underground waterways, they are filled with cool fresh water and are a chilly relief to the heat of the Yucatan. The cenotes have amazing visibility, easily 100m. We have visited three cenotes so far, two near Valladolid known as Dzitnup, and one 3km from Tulum pueblo.
The third cenote, "Gran Cenote", near Tulum is open to snorkelling and diving. We decided to try scuba diving in the fresh water cenote which was a really good dive. The natural light at Gran Cenote illuminated the cavern at times. At other times a flashlight was needed to see more than a few inches in front of you.