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 car rolls south along the Dalton Highway near Coldfoot, Alaska, USA, 03 September 2017. Stretching 414 miles (666 kilometers) north from central Alaska to Prudhoe Bay, the Dalton Highway is one of America's northernmost roads and arguably its most remote. (Photo by Jim Lo Scalzo/EPA)

Haitians pull a car atop a pushcart in Port-au-Prince, October 11, 1994. The price of gasoline has fallen to about $6 US per gallon since U.S. forces occupied Haiti. Before, gasoline had cost as much as $10 U.S. per gallon. (Photo by Eric Draper/AP Photo)

An Extinction Rebellion activist takes part in a protest in Berlin, Germany on October 5, 2020. (Photo by Michele Tantussi/Reuters)

A man walks in the street at the start of the new curfew to counter the COVID-19 in the center of Lyon, central France, Saturday, January 16, 2021. All of France will be under a stricter curfew starting Saturday at 6 p.m. for at least 15 days to fight the spread of the coronavirus. (Photo by Laurent Cipriani/AP Photo)

A Russian female military cadet marches in front of the Eternal Flame at the WWII memorial complex at Poklonnaya Hill in Moscow on February 17, 2021, during a rehearsal for the upcoming February 23's Defender of the Fatherland Day. (Photo by Alexander Nemenov/AFP Photo)

A demonstrator smashes a shop window during a protest condemning the arrest of rap singer Pablo Hasél in Barcelona, Spain, Saturday, February 20, 2021. A fifth night of peaceful protests to denounce the imprisonment of a Spanish rap artist once more devolved into clashes between police and fringe group members who set up street barricades and smashed storefront windows in Barcelona. (Photo by Joan Mateu/AP Photo)

A demonstrator skateboards in front of a burning police vehicle during a protest against a new proposed policing bill, in Bristol, Britain, March 21, 2021. The Police, Crime, Sentencing and Courts Bill would give forces in England and Wales more power to impose conditions on non- violent protests, including those deemed too noisy or a nuisance, with fines or jail for those convicted. (Photo by Peter Cziborra/Reuters)