In this picture taken on September 5, 2023, students practice contortionism at the Flower Studio in Ulaanbaatar. Mongolian circus performers fly through the air of a cavernous hall inspectors have warned could collapse at any time, one of the few places left to train if they hope to travel the world with their country's spectacular big top shows. (Photo by Pedro Pardo/AFP Photo)

Igor Perne (L), 53, an electronic engineer and a member of the International Virtual Aviation Organisation (IVAO), and fellow virtual pilot Franc Lavric gesture for the camera before taking off on a virtual flight in a flight simulator in Nova Vas, Slovenia November 13, 2014. In 2011, Perne, a lifelong flying enthusiast, bought parts of a written-off Cyprus Airways airliner and then spent two and a half years turning the entire nose of the scrapped aircraft into an elaborate flight simulator. (Photo by Srdjan Zivulovic/Reuters)

A long exposure image of embers flying off burnt out trees following the wind driven wildfire ranging in the mountain area near Rancho Cucamonga late 30 April 2014. Earlier in the day more than 1,500 homes were evacuated as the Etiwanda fire charred around 1,000 acres in San Barnardino National Forest. (Photo by Stuart Palley/EPA)

A picture taken on July 14, 2014 from a Boeing C135 refueling tanker shows two French Rafale fighter planes, flying over the French capital during the annual Bastille Day military parade on the Champs-Elysees in Paris. France has issued an unprecedented invitation to all 72 countries involved in World War I to take part in its annual Bastille Day military parade. (Photo by Franck Pennant/AFP Photo)

A helicopter flies close to a volcanic eruption which has begun in Fagradalsfjall near the capital Reykjavik on March 20, 2021 in Fagradalsfjall, Iceland. On Friday the Icelandic meteorological office announced a volcano, referring to a mountain located south-west of the Capital Reykjavik has erupted after thousands of small earthquakes in the area over the recent weeks. A no-fly zone has been established in the area. (Photo by Vilhelm Gunnarsson/Getty Images)

A woman walks on the stairs decorated with an image of two hands shaking to form the shape of the Korean Peninsula to support the upcoming inter- Korean summit, in downtown Seoul on September 17, 2018. South Korean President Moon Jae- in will fly to the North Korean capital on September 18, for his third summit with the North' s leader Kim Jong Un as a rapid diplomatic thaw takes hold on the peninsula despite stalled progress in denuclearisation talks between Pyongyang and Washington. (Photo by Jung Yeon-je/AFP Photo)

Hot air balloons fly over the sky in Chiang Mai province, northern Thailand, December 6, 2014. The two-day International Balloon festival 2014 featuring balloon pilots from Germany, Spain, Netherlands, Britain, and Czech Republic is held on December 06-07 2014 to celebrate Thai King Bhumibol Adulyadej's 87th birthday and also aimed to promote the tourism industry in Chiang Mai northern city. (Photo by Pongmanat Tasiri/EPA)