Children watch their classmate pour cold water on herself under the watch of a fitness coach at a local kindergarten in Russia's Siberian city of Krasnoyarsk, March 11, 2015. The program, which also involves sports training and sauna usage, has been practiced by the kindergarten for more than 15 years as they believe it has health benefits and keeps the children fit. Children start pouring cold water on themselves outdoors after about three years of training and undergoing medical tests, and the kindergarten is the only one in the region that practices these exercises, according to employees. (Photo by Ilya Naymushin/Reuters)

People affected by Hurricane Maria bathe in water piped from a creek in the mountains, in Naranjito, Puerto Rico, Thursday, September 28, 2017. Residents of the area drive to the pipes to bathe because they were left without water supplies by the damage caused by Hurricane Maria. The pipe was set up by a neighbor who ran it from a creek in his property to the side of the road in order to help those left without water. (Photo by Ramon Espinosa/AP Photo)

A woman carrying a bundle on her head wait in line to cross the border into Colombia through the Simon Bolivar bridge in San Antonio del Tachira, Venezuela, Sunday, July 17, 2016. Tens of thousands of Venezuelans crossed the border into Colombia on Sunday to hunt for food and medicine that are in short supply at home. It's the second weekend in a row that Venezuela’s government has opened the long-closed border connecting Venezuela to Colombia. (Photo by Ariana Cubillos/AP Photo)

A man takes a selfie next to a flooded street due to the overflowing of the Mapocho river during heavy rains in Santiago on April 17, 2016. Four million people in Santiago were without tap water Sunday after unusually heavy rain pounding central Chile triggered landslides that fouled the city's water supply and forced the closure of the world's biggest copper mine, officials said. (Photo by Martin Bernetti/AFP Photo)

Women wearing "Shiroshozoku" or the traditional white robe pray as they bathe in ice-cold water at the Teppozu Inari shrine in Tokyo, Japan, January 10, 2016. About 100 participants took part in the Shinto ceremony to purify their souls and wish for good health in the new year. (Photo by Yuya Shino/Reuters)

Ukrainian platoon commander Mariia talks on the phone in a position in the Donetsk region, Ukraine, Saturday, July 2, 2022. Ukrainian soldiers returning from the frontlines in eastern Ukraine’s Donbas region describe life during what has turned into a grueling war of attrition as apocalyptic. Mariia, 41, said that front-line conditions may vary depending on where a unit is positioned and how well supplied they are. (Photo by Efrem Lukatsky/AP Photo)

Two citizens splash hot water which is quickly frozen in the cold air on January 7, 2021 in Beijing, China. A strong cold wave sweeps across China as the Chinese capital Beijing recorded 19.5 Celsius below zero on 06 January morning, the lowest temperature since 1966, according to meteorological authorities. (Photo by Peng Yucai/VCG via Getty Images)

“Contrails (short for “condensation trails”) or vapour trails are artificial clouds that are the visible trails of condensed water vapour made by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets or, if the air is cold enough, tiny ice crystals”. – Wikipedia

Photo: An airplane leaves a vapor trail as it flies in front of he moon on January 17, 2007 above Hanover, Germany. (Photo by Alexander Hassenstein/Getty Images)