The singing group The D-Day Darlings take part in the unveiling ceremony of a permanent war memorial, created by artist and writer Fabian Peake, at St Pancras International railway station in London, Britain, November 8, 2018. (Photo by Peter Nicholls/Reuters)

A street entertainer waits for tourists in Havana, Cuba on October 2009. (Photo by Desmond Boylan/Reuters)

A man looks at a car hit by a post after a tornado ripped through a neighbourhood in Havana, Cuba on January 28, 2019. (Photo by Fernando Medina/Reuters)

A girl walks an Akita-inu dog dressed in a military uniform in Vladivostok, Russia on April 9, 2019. (Photo by Yuri Smityuk/TASS)

A reveler takes part in the 19th Gay Pride Parade at downtown Caracas, Venezuela on June 30, 2019. (Photo by Federico Parra/AFP Photo)

Dario Sammartino, of Italy, competes at the final table during the World Series of Poker at the Rio hotel-casino in Las Vegas Sunday, July 14, 2019. (Photo by Steve Marcus/Las Vegas Sun via AP Photo)

“The Supercell”. This shortlisted image by Dennis Oswald Huge farmland of was taken in south-west Oklahoma, US. (Photo by Dennis Oswald/2019 Weather Photographer of the Year/RMetS)

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)