The Y-40 Deep Joy is the worlds deepest pool. Y-40 is projected by Architect Emanuele Boaretto and supported by the “Boaretto Group Hotel and Resort”. The name Y-40 is inspired by mathematical symbols. “Y” is the ordinate axis of the Cartesian system and “–40” means the world's record depth or our pool- that is 40 meters underground. (Photo by Courtesy Y40 Deep Joy)

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.

New autopilot features are demonstrated in a Tesla Model S during a Tesla event in Palo Alto, California, 2015. Federal officials say the driver of a Tesla S sports car using the vehicle’s “autopilot” automated driving system has been killed in a collision with a truck, the first U.S. self-driving car fatality. The National Highway Traffic Safety Administration said preliminary reports indicate the crash occurred when a tractor-trailer made a left turn in front of the Tesla at a highway intersection. Joshua D. Brown, of Canton, Ohio, died in the accident May 7 in Williston, Florida, when his car's cameras failed to distinguish the white side of a turning tractor-trailer from a brightly lit sky and didn't automatically activate its brakes, according to government records obtained Thursday. (Photo by Beck Diefenbach/Reuters)

A soldier fires a rocket gun as Ukrainian soldiers in the Donetsk region, where the country's most intense clashes occur, attend intensive combat training by using both domestic and foreign weapons amid Russia-Ukraine war in Donetsk, Ukraine on May 08, 2023. Infantry is always prepared in a conflict where heavy weaponry like aircraft, helicopters, tanks and other heavy armored vehicles, artillery systems, and mortars are widely deployed on frontline. Combat readiness and experience training of the 57th Brigade of the Ukrainian army continues in Donetsk. (Photo by Muhammed Enes Yildirim/Anadolu Agency via Getty Images)

Shot by Bert Hardy, the black and white images show prisoners carrying out remedial tasks such as untying knots in post office string and sewing mail bags. Other intriguing shots show lags doing their daily one hour outdoor exercise, being frisked for contraband items by officers during a routine “rub down” and serving evening meals. Strangeways was designed by Alfred Waterhouse and cost £170,000 ($207,910) to build. The prison, famed for its prominent ventilation tower and imposing design, has become a local landmark. Here: A prison officer frisking prisoners during the “rub-down” at Strangeways Prison in Manchester, UK on November 1948. (Photo by Bert Hardy/Picture Post/Hulton Archive/Getty Images)

Participants wearing Zentai costumes, or skin-tight bodysuits from head to toe, take part in a march down the shopping district of Orchard Road during Zentai Art Festival in Singapore May 23, 2015. Close to 50 participants strutted down the busy shopping district during the Zentai art festival which is jointly organized by the Japanese embassy. The festival includes performances and discussions on Zentai from May 22 to from June 5. (Photo by Edgar Su/Reuters)

Axel, a research prototype rover for exploring the Moon, Mars and other planets, is remotely driven over rocks as engineers from Jet Propulsion (JPL) and grad students from Caltech (California Institute of Technology) demonstrate its mobile over the steep and rocky grounds of the JPL Mars Yard on January 14, 2009 in Pasadena, California. The rover is capable of descending cliffs or into craters and returning by a cable tethered to its starting point. Development of the Axel rover is a point effort funded by NASA Exploration Systems Mission Directorate (ESMD) and lead by Principal Investigator Issa Newnas and Co-Investigator and Caltech professor of mechanical engineering bio engineering Joel Burdick. (Photo by David McNew/Getty Images)