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 follower shows a ring of La Santa Muerte (The Saint of Death), a cult figure often depicted as a skeletal grim reaper, near at the saint's altar at Tepito neighborhood, in Mexico City January 1, 2015. Followers gather at the saint's altar at the start of the new year to leave offerings of apples, flowers, cigarettes, coloured candles and tequila to thank the saint for favours that have been granted and to ask for new ones in the new year. (Photo by Edgard Garrido/Reuters)

Participants compete during the Strong Race event near Tukums, Latvia, May 3, 2015. More than 4,000 people participated in this 9 km endurance race with 33 different obstacles. (Photo by Ints Kalnins/Reuters)

A cloud of black smoke billows out the exhaust pipe of John Robertson's diesel dragster as he runs down the track during the 2015 NHRA Kansas Nationals, Friday, May 22, 2015, at Heartland Park in Topeka, Kan. (Photo by Chris Neal/The Topeka Capital-Journal via AP Photo)

Sebastien Bourdais, of Colombia, makes a corner during practice for the IndyCar auto race Saturday, June 13, 2015, in Toronto. (Nathan Denette/The Canadian Press via AP)

A 10 km prologue dog sled race on the eve of the 2018 Beringia dog sled race in Russia' s Far East; the prologue race is part of the 2018 Russian Winter Dog Powered Sports Cup in Petropavlovsk-Kamchatsky, Russia on March 4, 2018. (Photo by Yuri Smityuk/TASS)

The images of U.S. Democratic presidential candidate Hillary Clinton (L) and Republican Presidential candidate Donald Trump are seen painted on decorative pumpkins created by artist John Kettman in LaSalle, Illinois, U.S., June 8, 2016. (Photo by Jim Young/Reuters)

A participant peeks from his costume before the start of the the annual London Pantomime Horse Race in Greenwich, Britain December 13, 2015. (Photo by Neil Hall/Reuters)