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

A swimmer swims by a swan in The Serpentine in Hyde Park, following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 26, 2020. (Photo by John Sibley/Reuters)

A runner participates in the Santa Run 10K race in Caracas, Venezuela, Sunday, December 19, 2021. This is the first Santa Run since the start of the pandemic. (Photo by Ariana Cubillos/AP Photo)

A woman wearing a kimono performs an uchimizu ritual outside a pachinko game parlor in Tokyo June 30, 2015. The splashing of water onto the hot asphalt in summer is an old Japanese tradition meant to cool down the air as the water evaporates. (Photo by Thomas Peter/Reuters)

Two costumed reveler seen at the City center where normally thousands of revelers dressed in carnival costumes would celebrate the Rose Monday parade on the streets in Mainz, Germany, 15 February 2021. The Rose Monday Parade has been cancelled due to the coronavirus Covid-19 pandemic. (Photo by Ronald Wittek/EPA/EFE)

Daniel Cheong, a dog behaviorist and trainer, steps over a leash as he walks a pack of dogs in Arlington, Va. on November 13, 2018. (Photo by Ricky Carioti/The Washington Post)

A serviceman of Russia's Emergencies Ministry wearing protective gear disinfects Moscow's Leningradsky railway station on May 19, 2020, amid the COVID-19 coronavirus pandemic. (Photo by Kirill Kudryavtsev/AFP Photo)