Pole dancers in Mexico have taken to the streets to celebrate their sport and show others the skills involved. The Pole Dance National Day celebration saw pole dancers gather in parks, outdoor gyms and on streets, using street lamps, sign posts and other objects to put on displays across Mexico City. Photo: A woman performs a pole dancing routine on a pedestrian bridge during the national day celebration of “Urban Pole” dance in Monterrey June 8, 2014. (Photo by Tomas Bravo/Reuters)

Matachines dancers participate in a religious festival in Saltillo, Mexico, April 17, 2016. Matachines dancing is a masked dance introduced by Spanish missionaries, and has been adopted by cultures from Peru to northern Mexico. It is performed to show respect to Mother Mary or the Guadalupe Virgin, a saint, or to simply worship God. (Photo by Daniel Becerril/Reuters)

Migrants ride on top of a northern bound train toward the US-Mexico border in Juchitan, southern Mexico, Monday, April 29, 2013. Migrants crossing Mexico to get to the U.S. have increasingly become targets of criminal gangs who kidnap them to obtain ransom money. (Photo by Eduardo Verdugo/AP Photo)

Young “scissors” dancers pose after performing in a national scissors dance competition at Lima's Exposition Park, May 18, 2014. The Danza de las tijeras, or scissors dance, is a traditional dance from the Peruvian southern region of the Andes, in which two or more performers take turns dancing while accompanied with music from a harp and a violin. Dancers would display various skills and moves, which include cutting the air with the use of a scissors. (Photo by Enrique Castro-Mendivil/Reuters)

Margaret Morris dancers exercising on the sands at Saint-Idesbald. (Photo by Fox Photos/Getty Images). August 1929

Dressers make last minute adjustments to the costumes of dancers performing as horses during a press preview of American artist Nick Cave's first major work shown in Australia, entitled HEARD.SYD in Sydney, November 8, 2016. Over several days the live art performance will feature 30 “horses” dancing to live percussion beats in suits made from coloured raffia plant fibres. (Photo by Jason Reed/Reuters)

A cenote is a natural phenomenon, a sinkhole in the Earth’s surface. The Yucatan Peninsula in Mexico has an estimated 7,000 cenotes because it is primarily made up of porous limestone. For millions of years, rainfall slowly ate away at the limestone and a huge system of underground caves and caverns was formed. Many filled with water from rain or from the underground water table. When the roof of a water filled cave collapses, a cenote is born. The water found in a cenote may be fresh water, salt water, or both. Structurally it may be completely open, like a lake, almost completely closed with just a small opening at the top, or somewhere in between.

Pod of dolphins surf effortlessly through the waves in the wild traveling at speeds up to 20 mph. (Photo by Greg Huglin)