The Mesoamerican Barrier Reef is the second largest barrier reef in the world. This Barrier Reef begins at the top of the Yucatan Peninsula and runs south to Belize and beyond. This reef system, with over 500 fish species and 100 coral types, gives you some of the best diving opportunities in the area. Riviera Maya is well known due to the anual migration of hundreds of whales sharks. They concentrate around Isla Mujeres where swimming with this hugh sharks is possible in the summer. The most outstanding areas are Cozumel Island and the Xpu-Ha reef where there is a possibility to dive with Bull sharks in winter. The Riviera Maya also offers a unique dive experience like no other in the world: cavern diving of Cenote! The fresh water of the Yucatan runs underground and the caverns & caves offer an unique and adventurous dive experience. The number of cenotes or sink holes of Yucatan is between 7000 to 8000. Many of the cenotes are connected and formed the largest underwater cavern system in the world.