The Yucatan Peninsula is situated in the southeastern part of Mexico.  It is nested between the Caribbean Sea in the east, the Gulf of Mexico in the west, and Sierra Madre del Sur in the south. The peninsula is split into three federal states - Quintana Roo, Campeche and Yucatan. The Yucatan is 300 km long and 250 km wide (150,000 square km).  The altitude increases gradually from the coastline to the center without exceeding 50 meters above sea level.  The climate is tropical with an annual rainfall of 700 mm/year in the northwestern part to 1700 mm in Cozumel.  Ninety percent of the rainfall happens during the rainy season from May to October. However, the weather rarely alters the diving conditions. The average temperature is 25°C/ 76°F.

The Yucatan Peninsula is a huge limestone plateau measuring up to several thousand feet in depth in some areas. There are no surface rivers visible. Rainwater quickly seeps through the porous limestone, entering enormous caves and caverns.  Natural collapses create an entrance to the water table. In this part of Mexico, these natural openings are referred to as Cenotes (from the Mayan word "d'zonot", meaning Sacred Well).  Cenotes are found by the thousands all over the Yucatan.  Cenotes are the gateway to hundreds of miles of beautifully and highly decorated cave systems.

For hundreds of years, these same cenotes played a large ceremonial role in the life of ancient Mayan civilization, and a more practical one as a source of water for the large populations. The Mayan civilization flourished from 4 BC to the 10th century of our era in Yucatan, Belize, Guatemala, and northern Honduras. Ruins, such as Chichen Itza, Palenque, Copan, and Tikal, the Mayan language and the present artistic demeanor are strong reminders of the prominence of this past civilization.