An artist takes part in the festival “Statues en Marche” in Marche-en-Famenne, Belgium, July 20, 2019. Living statues are a common sight in many city centers, but it is rare to see such a diverse range of this peculiar form of street art for which performers must keep still for painfully long periods of time to create the desired illusion. (Photo by Yves Herman/Reuters)

Artists called “Le couple en chocolat” take part in the festival “Statues en Marche” in Marche-en-Famenne, Belgium, July 22, 2018. Living statues are a common sight in many city centres, but it is rare to see such a diverse range of this peculiar form of street art for which performers must keep still for painfully long periods of time to create the desired illusion. (Photo by Yves Herman/Reuters)

Guest gather in the street as the wait to attend the annual New York City Diner en Blanc, August 22, 2017 held this year at the plaza at Lincoln Center. The Diner en Blanc, the worlds only viral culinary event, a chic secret pop-up style picnic from France, the outdoor site – always a landmark location – is revealed at the last-minute. Guests are asked to dress entirely in elegant white, bring a picnic basket of food, fine china and silverware, white tablecloths, table and chairs. (Photo by Timothy A. Clary/AFP Photo)

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)

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.

An activist kicks the shields of the military police officers during a demonstration in the military zone of the 27th infantry battalion in Iguala, Guerrero, January 12, 2015. Activists and relatives of the 43 missing trainee teachers from Ayotzinapa's teacher training college broke into the military zone, located less than a mile from where the students went missing, in an attempt to look for the missing students.The remains of only one of the 43 students has been identified so far. (Photo by Jorge Dan Lopez/Reuters)

A clown plays the violin during the XXI Convention of Clowns, at the Jimenez Rueda Theatre, in Mexico City, Mexico, October 19, 2016. In the wake of the creepy clown sightings in several states of North and South Americas and Europe that caused widespread panic, professional clowns from across Latin America came together at an annual convention in Mexico to give a serious message: “We are clowns, not killers!”. Around 200 clowns took part in the 21st International Clown Convention, dressed in bright coloured clothes and makeup, and chanted the word as they clicked group pictures to counter the “creepy clown” craze. (Photo by Carlos Jasso/Reuters)

s*x workers, wearing decorative skull masks, march through the streets in downtown Mexico City, Friday, October 28, 2016. The women march with candles to an altar dedicated to their departed colleagues, many who died violently at the hands of their customers. This annual procession, tied to the Day of the Dead festivities, has taken place for more than 20 years. (Photo by Eduardo Verdugo/AP Photo)