“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)

A moon bear rests in a pool inside an enclosure at the Vietnam bear rescue centre, in Tam Dao national park, Vinh Phuc, Vietnam, 09 July 2019. The center is operated by international organization Animals Asia. There are currently 184 bears living at the the Vietnam Bear Rescue Centre. It is estimated that there are less than a few hundred bears left in the wild in Vietnam. According to the latest data from the Ministry of Agriculture and Rural development, around 600 bears are still being kept on farms. In Vietnam, Animals Asia has rescued a total of 209 sun bears and moon bears. (Photo by Minh Hoang/EPA/EFE/Rex Features/Shutterstock)

Storm clouds blanket the sky over Great American Ball Park as Starlin Castro #13 of the Chicago Cubs fields a ground ball in the fifth inning against the Cincinnati Reds as on July 7, 2014 in Cincinnati, Ohio. (Photo by Jamie Sabau/Getty Images)

A round circle of smoke coming from the mouth of the Etna volcano is seen in the sky during an eruption on the southern Italian island of Sicily April 11, 2013. Mount Etna is Europe's tallest and most active volcano. (Photo by Antonio Parrinello/Reuters)

A fireworks display decorates the night sky to celebrate the New Year, as crowds of people look on, at Kim Il Sung Square in Pyongyang, North Korea, early Friday, January 1, 2021. (Photo by Jon Chol Jin/AP Photo)

A person watches Mount Etna, Europe's most active volcano, light up the night sky with eruptions, as seen from Piazzale Funivia dell'Etna, Italy on December 1, 2023. (Photo by Etna Walk/Giuseppe Distefano/Handout via Reuters)

Swimmers in the Sky Pool, a transparent swimming pool suspended 35 meters above ground between two apartment buildings, during hot weather in Nine Elms, central London on Monday, August 12, 2024. (Photo by James Manning/PA Images via Getty Images)

1: Dubai's Burj Khalifa is the tallest building in the world, but perhaps not for long. Saudi Arabia has announced plans to build a 1 kilometer (3,280 foot) tower into the sky, to be named the Jeddah Tower, scheduled for completion in 2020. The Burj Khallifa currently stands at 2,716 ft. (Photo by Matthias Seifert/Reuters)