Seven divers perform a mass dive from 19 metres (62 ft) after the second training session of the seventh and final stop of the Red Bull Cliff Diving World Series at the famous Ik Kil cenote in Yucatan, Mexico, on October 16th 2014.
A cenote is a natural pit or sinkhole resulting from the collapse of limestone bedrock that exposes groundwater underneath. Ik Kil is located in the northern center of the Yucatán Peninsula and is part of the Ik Kil Archeological Park near Chichen Itza. It is open to the public for swimming and is often included in bus tours.
The cenote is open to the sky with the water level about 26 metres (85 ft) below ground level. There is a carved stairway down to a swimming platform. The cenote is about 60 metres (200 ft) in diameter and about 40 metres (130 ft) deep. There are vines which reach from the opening all the way down to the water along with small waterfalls. [source]