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)

Majesty Davis, 3, cries while visiting Santa Claus, who sits behind a plexiglass divider due to the coronavirus disease (COVID-19) pandemic, at the Willow Grove Park Mall in Willow Grove, Pennsylvania, U.S. November 14, 2020. (Photo by Mark Makela/Reuters)

The Soyuz MS-17 spacecraft carrying the crew formed of Kathleen Rubins of NASA, Sergey Ryzhikov and Sergey Kud-Sverchkov of the Russian space agency Roscosmos blasts off to the International Space Station (ISS) from the launchpad at the Baikonur Cosmodrome, Kazakhstan on October 14, 2020. (Photo by Russian space agency Roscosmos/Handout via Reuters)

A guest proposes to his companion as they arrive for the screening of “Mektoub, My Love: Intermezzo” during the 72nd annual Cannes Film Festival, in Cannes, France, 23 May 2019. The movie is presented in the Official Competition of the festival which runs from 14 to 25 May. (Photo by Julien Warnand/EPA/EFE)

These two ladies received some important messages on Valentine's night in Manchester, England on February 14, 2020. Brits celebrated Valentine's Day in style last night – proving you can have a good time even if you don't have a partner. (Photo by Mercury Press/The Sun)

A farmer carries a bundle of wheat after harvesting it from a field in the Gharbia Governorate, as Egypt ramps up efforts to slow the spread of the coronavirus disease (COVID-19), Egypt on May 14, 2020. (Photo by Mohamed Abd El Ghany/Reuters)

A skier in a festive costume attempts to cross a pool of water at the foot of a ski slope while competing in the annual Gornoluzhnik amateur event to mark the end of the ski season at the Bobrovy Log ski resort in the suburbs of the Siberian city of Krasnoyarsk, Russia, April 14, 2019. (Photo by Ilya Naymushin/Reuters)

An Iraq fan poses before the World Cup 2022 Qualifier 2nd round Group C football match between Iraq and Iran at Amman International Stadium in Amman, Jordan on November 14, 2019. (Photo by Muhammad Hamed/Reuters)