A woman cools off at a fountain in central Cordoba, southern Spain, 11 August 2021. Andalucia was put on orange alert for high temperatures, with a new heatwave forecast to reach temperatures of over 41 degrees Celsius in the region. (Photo by Salas/EPA/EFE)

A man walks his dog as the sun sets in a park in Frankfurt, Germany, Monday, September 18, 2017. Cool damp weather is set to continue in this part of Germany for the next few days with temperatures in the mid teens Celsius. (Photo by Michael Probst/AP Photo)

A Palestinian boy dips in a natural spring to cool off during a heat wave, amid concerns about the spread of the coronavirus disease (COVID-19), near Jericho in the Israeli-occupied West Bank on May 17, 2020. (Photo by Mohamad Torokman/Reuters)

A brown bears cools off in a pool at the bear sanctuary near the village of Mramor, on August 18, 2020. The bear sanctuary was closed for visitors on August 18, as part of safety measures to curb the spread of the COVID-19 (novel coronavirus) disease. (Photo by Armend Nimani/AFP Photo)

People cool off at Crown Fountain in Millennium Park as temperatures reached a record high of 97 degrees Fahrenheit on June 17, 2024 in Chicago, Illinois. Temperatures in the city are expected to reach highs in the 90s for the remainder of the week. (Photo by Scott Olson/Getty Images)

Edgar Sanchez stops on a walk with his dogs who cool off in a pool beside a fire hydrant sprayer, Saturday, June 22, 2024, in the Lower East Side neighborhood of New York. (Photo by John Minchillo/AP Photo)

Broomfield Samson, a rare breed Suffolk punch, and his rider, Alison Carroll, cool off in the River Lune at Loyne Bridge near Gressingham in Lancashire, UK on May 21, 2024. (Photo by James Glossop/ The Times & Sunday Times)

“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)