Nikolai Vasilyev, 64, dressed as Father Frost, the Russian equivalent of Santa Claus, water-skis along the Yenisei River outside the Siberian city of Krasnoyarsk, Russia December 19, 2017. Vasilyev, former teacher of the Siberian State Aerospace University, constructed the water skis out of plastic foam and designed the sticks to propel him forward, while travelling on the water surface. (Photo by Ilya Naymushin/Reuters)

A man who was set on fire by people accusing him of stealing during a rally against Venezuela's President Nicolas Maduro runs amidst opposition supporters in Caracas, Venezuela, May 20, 2017. (Photo by Marco Bello/Reuters)

Three cabaret dancers sit glum-faced in the Windmill Theatre's canteen upon hearing the news that the theatre's owners have sold out to a cinema company, on October 02, 1964. The theatre, which was the first to include nudity in its shows, has been able to cope with competition from a growing number of West End strip clubs. (Photo by Hulton-Deutsch Collection/CORBIS/Corbis via Getty Images)

A young fan watches as Green Bay Packers running back AJ Dillon (28) tries his best to ride her bicycle to training camp on Monday, August 1, 2022, at Ray Nitschke Field in Green Bay, Wis. (Photo by Dan Powers/USA TODAY Sports)

Lightning streaks across the sky as lava flows from a volcano in Eyjafjallajokul April 17, 2010. (Photo by Lucas Jackson/Reuters)

A picture taken on October 17, 2014 in Vevey shows a giant fork designed by Switzerland's artist Jean-Pierre Zaugg to commemorate Nestle's Alimentarium Food Museum 10th anniversary. World's biggest food company, Swiss Nestle Group announced results sales down by 3.1% for the first nine months of 2014 to 66.2 billion Swiss francs (55.1 billion euros). (Photo by Fabrice Coffrini/AFP Photo)

To an outsider, their passion is at times illegal and often on the verge of life and death. But climbing rooftops of high-rise buildings and exploring abandoned facilities is in the blood of these young Muscovites. The small group calls itself “Rudex”, which stands for “roof and decay exploration”, and is akin a Western youth craze known as urbex or “urban exploration” of man-made structures. Here: Urban explorer Vad Him of Rudex team jumps whilst on a rooftop in Moscow, Russia, August 14, 2017. (Photo by Maxim Shemetov/Reuters)

A tourist train is decorated with Christmas lights in Bogotá, Colombia on December 10, 2017. (Photo by Jaime Saldarriaga/Reuters)