“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 young vendor hawks food on a market in Kara in the state of Ogun, on September 23, 2015. Nigeria imposed tight movement restrictions in the restive northeast after Boko Haram bombings that killed more than 100 raised fears of fresh attacks over the Eid al-Adha festival. The military said the use of all vehicles would be banned throughout Borno state during the Muslim festival, which is known as Sallah in Nigeria and marked with two days' public holiday from Thursday. (Photo by Pius Utomi Ekpei/AFP Photo)

A rainbow forms on water from a spray machine used to suppress coal dust at the Krasnogorsky open pit coal mine, operated by Mechel PJSC, in Mezhdurechensk, Russia, on Monday, July 19, 2021. Russia’s government is betting that coal consumption will continue to rise in big Asian markets like China even as it dries up elsewhere. (Photo by Andrey Rudakov/Bloomberg)

A protester is taken away by law enforcement officers during a rally held by opposition supporters on the parliamentary election day in Almaty, Kazakhstan on January 10, 2021. Dozens of activists were detained in at least three major cities, including the capital, Nur-Sultan, and Almaty, with reports of independent observers being denied access or detained at some polling stations. (Photo by Petr Trotsenko/Radio Free Europe/Radio Liberty)

Ethnic Miao men wearing traditional masks smear dust on a woman's face to wish her good luck during local celebration event for Lunar New Year in Liuzhou, Guangxi Zhuang Autonomous Region, China, February 16, 2016. (Photo by Reuters/Stringer)

Carnival revellers dressed as “Peliqueiros” run along a street in the village of Laza, Spain February 11, 2018. “Peliqueiros”, or ancient tax collectors, pursued villagers through the streets ringing their cowbells and hitting villagers with their sticks. (Photo by Miguel Vidal/Reuters)

In this September 16, 1983 file photo, actor and bodybuilder Arnold Schwarzenegger shows off his new U.S. citizenship papers as Maria Shriver, daughter of Sargent and Eunice Shriver, looks on at the Shrine Auditorium in Hollywood, Calif. (Photo by Wally Fong/AP Photo)

Animal rights activists perform, demanding the abolition of bullfights, during a demonstration in Medellin, Colombia February 11, 2018. The Colombian Constitutional Court overruled on February 7, 2018, a judgment that allowed to hold a referendum regarding bullfights. (Photo by Fredy Builes/Reuters)