The Ik Kil Cenote, Mexico
A cenote is a natural pit, or sinkhole, resulting from the collapse of limestone bedrock that exposes groundwater. This marvellous geological feature is located in the northern center of the Yucatán Peninsula and is part of the Ik Kil Archeological Park near Chichen Itza. Bones and pieces of jewelry were found in the deep waters of this cenote by archaeologists and speleologists which led to believe that this site was considered sacred by the Mayans who used the site as a location for human sacrifice to their rain god, Chaac. It is open to the public for swimming.