Dr. Christopher Brown (R), the Director of the Ashmolean, talks with Colin Harrison, the Ashmolean's Senior Curator of European Art, in front of a painting by Edouard Manet entitled “Portrait of Mademoiselle Claus” from 1868 in the Ashmolean Museum on February 24, 2012 in Oxford, England. The painting has been sold to a foreign buyer for 28.35 million GBP, however the Government has extended a temporary export bar on the artwork until August to give the Ashmolean an opportunity to raise funds to retain the painting in the UK. (Photo by Oli Scarff/Getty Images)

Miley Cyrus attends the Heavenly Bodies: Fashion & The Catholic Imagination Costume Institute Gala at The Metropolitan Museum of Art on May 7, 2018 in New York City. (Photo by Mike Coppola/MG18/Getty Images for The Met Museum/Vogue)

Two female revelers engage in a beer drinking contest in the Hacker Pschorr tent on the first day of the 2017 Oktoberfest beer fest on September 16, 2017 in Munich, Germany. Oktoberfest is the world's largest beer celebration and typically draws over six million visitors over its three-week run. Oktoberfest includes massive beer tents, each run by a different Bavarian brewer, as well as amusement rides and activities. (Photo by Philipp Guelland/Getty Images)

Alexandre Vinokourov of Kazakhstan from the T-Mobile Team is chased by eccentric german inventor Didi Senft dressed as the red devil during the stage 16 of the 92nd Tour de France between Mourenx and Pau on July 19, 2005, France. (Photo by Friedemann Vogel/Bongarts/Getty Images)

Bella Hadid attends “The Unknown Girl (La Fille Inconnue)” Premiere during the 69th annual Cannes Film Festival at the Palais des Festivals on May 18, 2016 in Cannes, France. (Photo by Alberto Pizzoli/AFP Photo)

“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)

Rihanna and Drake perform at the BRIT Awards at the O2 arena in London, Britain, February 24, 2016. (Photo by Stefan Wermuth/Reuters)

Bella Thorne out and about, Los Angeles, USA on June 14, 2017. (Photo by Broadimage/Rex Features/Shutterstock)