A visitor jumps for a photograph on the world's highest and longest glass-bottomed bridge above a valley in Zhangjiajie in China's Hunan Province on August 21, 2016. The bridge, which opened to the public on a trial basis on Saturday, spans 430 meters (1,410 feet) and rises about 300 meters (984 feet) above a valley in a scenic zone, making it the world's highest and longest glass-bottomed bridge according to Chinese state media. (Photo by Fred Dufour/AFP Photo)

Yuri Gagarin does not always show up in full-scale astronautics. In this picture he smiles during his summer vacation in Sochi, Russia in 1961 with sunglasses and sunhat in the camera. (Photo by Imago/Eastnews)

A home-made steam train, designed by Pavel Chilin, rides on a make-shift railway across country house neighborhood in the settlement of Ulyanovka in Leningrad region, Russia on November 4, 2019. (Photo by Anton Vaganov/Reuters)

A Sotheby's employee poses with a “Return of the Jedi” promotional C-3PO Helmet 1983, estimated at £15,000-£25,000 created by George Lucas' visual effects company during a photocall at Sotheby's in London, Britain on December 6, 2019. (Photo by Thomas Mukoya/Reuters)

A Iranian man walks with a sheep he bought at a market in the capital Tehran on September 12, 2016, as Muslims mark the first day of the Eid al-Adha (Feast of the Sacrifice) holiday. Muslims across the world celebrate the annual festival of Eid al-Adha, or the festival of sacrifice, which marks the end of the Hajj pilgrimage to Mecca and commemorates prophet Abraham's readiness to sacrifice his son to show obedience to God. (Photo by AFP Photo/Stringer)

A girl collects drinking water at Dala river outside Yangon, Myanmar March 3, 2016. Some 650 million people, or one in 10 of the world's population, have no access to safe water, putting them at risk of infectious diseases and premature death. Dirty water and poor sanitation can cause severe diarrhoeal diseases in children, killing 900 under-five a day across the world, according to United Nations estimates. (Photo by Soe Zeya Tun/Reuters)

Armed female members of the militant Palestinian group Islamic Jihad carry Kalashnikov assault rifles as they take part in a rally to protest against US President Donald Trump's decision to recognise Jerusalem as the capital of Israel, in Gaza City on December 11, 2017. (Photo by Mohammed Abed/AFP Photo)

Models kiss the back of another model, with a message on her back, during the grand finale of Lotus Make-up India Fashion Week based on “Rainbow” theme, an emblem for the LGBTQ community, in New Delhi, India, Sunday, October 14, 2018. According to Fashion Design Council of India, the “Rainbow” show, wherein 40 designers showcased their creations, was a tribute to mark the historic judgement by the Supreme Court of India which struck down a colonial-era law that made homosexual acts punishable by up to 10 years in prison. (Photo by Altaf Qadri/AP Photo)