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)

Russia's Alexandra Stepanova and Ivan Bukin perform during the ice dance free dance program at the Rostelecom Cup ISU Grand Prix of Figure Skating in Moscow November 15, 2014. (Photo by Grigory Dukor/Reuters)

“Aquarium or Akvarium (Russian: Аквариум) is a Russian rock group, formed in Leningrad in 1972 by Boris Grebenshchikov (Борис Гребенщиков), then a student of Applied Mathematics at Leningrad State University, and Anatoly (George) Gunitsky, then a playwright and absurdist poet”. – Wikipedia

Flashmob: Water Battle on All-Russian Exhibition Center in Moscow, Russia, on August 5, 2012. (Photo by Lilja Dal)

International film actress Gillian Anderson pictured on the rooftop of the Ritz-Carlton Hotel overlooking Red Square in a British Airways Business Class seat to launch the British Airways long haul service on the London – Moscow route on March 6, 2012 in Moscow, Russia. (Photo by Gareth Cattermole/Getty Images For British Airways)

Models backstage ahead of the St George New Generation show at Mercedes-Benz Fashion Week Australia 2015 at Carriageworks on April 16, 2015 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)

A model walks the runway during the Versace show as part of Paris Fashion Week Haute Couture Spring/Summer 2015 on January 25, 2015 in Paris, France. (Photo by Pascal Le Segretain/Getty Images)