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)

The Royal Air Force Red Arrows perform the “Gypo Split” during their first public aerobatic display since the tragic death of Flt Lt Jon Egging on September 2, 2011 in Chatsworth, England. (Photo by Christopher Furlong/Getty Images)

In this undated photo released Tuesday April 13, 2021, by Russian Defense Ministry Press Service, A Tu-160 strategic bomber of the Russian air force is shown on a training mission somewhere in Russia. Russian Defense Minister Sergei Shoigu on Tuesday described a massive military buildup in western Russia as part of drills intended to check the armed forces' readiness amid the threats posed by NATO. (Photo by Vadim Savitsky/Russian Defense Ministry Press Service via AP Photo)

Sinabung mount spews ash to the air during an eruption near from Karo, North Sumatra on January 7, 2014. An Indonesian volcano that has erupted relentlessly for months shot volcanic ash into the air 30 times on January 4, forcing further evacuations with more than 20,000 people now displaced, an official said. (Photo by Sutanta Aditya/AFP Photo)

Race fans watch from the grandstands as Air Force One circles the Daytona International Speedway as President Donald Trump makes his arrival to attend the NASCAR Daytona 500 auto race at Daytona International Speedway, Sunday, February 16, 2020, in Daytona Beach, Fla. (Photo by Jim Topper/AP Photo)

A girl poses at an entrance of her house next to a bomb dropped by the U.S. Air Force planes during the Vietnam War, in the village of Ban Napia in Xieng Khouang province, Laos September 3, 2016. From 1964 to 1973, U.S. warplanes dropped more than 270 million cluster munitions on Laos, one-third of which did not explode, according to the Lao National Regulatory Authority. (Photo by Jorge Silva/Reuters)

A Falcon 9 SpaceX rocket, with a payload of 60 satellites for SpaceX's Starlink broadband network, lifts off from Space Launch Complex 40 during a time exposure at the Cape Canaveral Air Force Station in Cape Canaveral, Fla., Thursday, May 23, 2019. (Photo by Malcolm Denemark/Florida Today via AP Photo)

Over 30 Douglas C-47 Skytrains (Dakotas) making final preparations for flight formation practice before the 75th D-Day Anniversary flight to Normandy in Duxford, England on June 4, 2019. (Photo by UK Air Force Images)