An activist of the anti-G8 forum “Block G8” shows his middle finger to a police helicopter passing overhead June 07, 2007 at Bollhagen, near Heiligendamm, Germany. (Photo by Carsten Koall/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)

Russian-born artist Vlad Korneev poses for a picture in his museum called “Designpanoptikum, Museum For Extraordinary Objects” on November 4, 2010 in Berlin, Germany. The museum displays objects whose outward appearance was determined by function rather than form, he says, and are the result of a collection he started while accumulating props for his photographic works. (Photo by Sean Gallup/Getty Images)

German model Alena Gerber poses wearing a full chocolate dress during the presentation of chocolate dresses designed by German bakery group Lambertz on January 21, 2010 in Munich, Germany. (Photo by Alexandra Beier/Getty Images)

An inflatable snake hovers during a performance by the French street theater company Plasticiens Volants on September 4, 2011 in Berlin, Germany. The spectale, featuring gigantic flying inflatable fairy-tale creatures and performers on stilts and in costume was a part of celebrations for the 125th anniversary of the Kurfuerstendamm, known locally as the Ku'damm, a shopping boulevard. (Photo by Adam Berry/Getty Images)

Zookeeper Michael Horn holds up Kit and Kitty, the twin red pandas born in June on the first day of their introduction into their new enclosure at Tierpark Zoo on September 13, 2011 in Berlin, Germany. The red panda (Ailerus fulgens) is a rare mammal native to the eastern Himalayas and southwestern China. (Photo by Sean Gallup/Getty Images)

Kindergartner Cameron McManus, 5, watches as a fellow student has his portrait made during “picture day” at Rogers International School on September 23, 2020 in Stamford, Connecticut. Students lined up outside to be photographed while socially distanced due to COVID-19 precautions. Most students at Stamford Public Schools are taking part in a hybrid education model, attending in-school classes every other day and distance learning the rest. (Photo by John Moore/Getty Images)

Models sit backstage during an outdoor show at Dakar Fashion week on December 12, 2020 just outside Dakar, Senegal. With Senegal's low incidence of Covid-19, Dakar's marquee fashion event looked markedly more normal than its counterparts in other global capitals, whose fashion weeks were heavily curtailed or canceled. (Photo by Finbarr O'Reilly/Getty Images)