Su Daocheng rides his home-made mechanical horse vehicle on a street in Shiyan, Hubei province January 18, 2015. Su spent 2 months making this 1.5 metre high and 2 metre long horse, which weighed 250 kilograms with 4 legs and 2 supportive wheels, local media reported. (Photo by Reuters/Stringer)

A resident types a text message on her mobile phone, as she sits on a bench made from a tree, which is a creation by Brazilian artist Hugo Franca at Largo da Batata square in Sao Paulo March 17, 2015. Franca, a designer from Sao Paulo is working with the city to make use of fallen trees to turn them into sculpture furniture to line the city's parks, streets and plazas. Brazil's largest city was slammed by several strong storms this rainy season that brought with them heavy rain, lightning and winds as high as 90 kilometres (55 miles) per hour. (Photo by Nacho Doce/Reuters)

A dancer waits to perform during festivities marking the start of the annual harvest festival of “Onam” in Kochi, India, August 19, 2015. The ten-day-long Hindu festival is celebrated annually in India's southern coastal state of Kerala to commemorate the return of King Mahabali to his beloved subjects. (Photo by Sivaram V/Reuters)

A man enters an adult amusement establishment in Shinjuku's nightlife district of Kabukicho in Tokyo, August 27, 2015. (Photo by Thomas Peter/Reuters)

A man and his broomstick are bringing magic to Instagram with these uplifting snaps. Daisuke Kujiraoka, 36, from Tokyo, Japan, snapped himself levitating across the country and uploaded them to the social media site. The quirky artist has posed with aeroplanes and cars appearing to float in mid-air Harry Potter-style. (Photo by Daisuke Kujiraoka/Caters News/Mercury Press)

People try to get a roast chicken at the first Costco outlet in China, on the stores opening day in Shanghai on August 27, 2019. China has proved a brutal battleground for overseas food retailers in recent years, with many failing to understand consumer habits and tastes as well as local competitors building a stronger presence. (Photo by Hector Retamal/AFP Photo)

Margaret Morris dancers exercising on the sands at Saint-Idesbald. (Photo by Fox Photos/Getty Images). August 1929

“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)