People stand under a giant Czech flag as they arrive to light candles at the base of a statue of St. Wenceslas to commemorate the death of former Czech President Vaclav Havel on December 18, 2011 in Prague, Czech Republic. Havel, who led the Velvet Revolution that forced communist rule in Czechoslovakia to crumble in 1989, died in the early morning today in his sleep at the age of 75. (Photo by Sean Gallup/Getty Images)

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)

Doctor Boaz Zissu of the Bar Ilan University shows the inscription on a 2,000-year-old ossuary at the Rockefeller Museum on June 30, 2011 in Jerusalem, Israel. The Israel Antiquities Authority have confirmed the credibility of the ancient ossuary, otherwise known as a stone chest in which to store bones, as bearing the name of a relative of the high priest Caiaphas from the New Testament. Laboratory tests have come back saying that the inscription with the name of “Miriam daughter of Yeshua son of Caiaphas, priest of Maaziah from Beth Imri” is both “genuine and ancient”. (Photo by Uriel Sinai/Getty Images)

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)

Thai classical dancers perform for Phra Phrom, the Thai interpretation of the Hindu god Brahma, at the Erawan Shrine in Bangkok, Thailand, Friday, September 4, 2015. Thai authorities unveiled the restored centerpiece Friday of the Erawan Shrine, in the latest bid to restore confidence among Bangkok's tourism and business communities almost three weeks after a deadly bombing. (Photo by Sakchai Lalit/AP Photo)

An artwork entitled “Are you still mad at me?” by John Isaacs is displayed at the Death: A Self-portrait exhibition at the Wellcome Collection on November 14, 2012 in London, England. The exhibition showcases 300 works from a unique collection by Richard Harris, a former antique print dealer from Chicago, devoted to the iconography of death. The display highlights art works, historical artifacts, anatomical illustrations and ephemera from around the world and opens on November 15, 2012 until February 24, 2013. (Photo by Peter Macdiarmid)

A man, right, throws a chair at a business window as another man tries to restrain a woman attempting to stop the damage, after march to City Hall for Freddie Gray, Saturday, April 25, 2015 in Baltimore. Gray died from spinal injuries about a week after he was arrested and transported in a police van. (Photo by Alex Brandon/AP Photo)

Revellers celebrate the death of Britain's former prime minister Margaret Thatcher in Brixton, south London April 8, 2013. Margaret Thatcher, the “Iron Lady” who transformed Britain and inspired conservatives around the world by radically rolling back the state during her 11 years in power, died on Monday following a stroke. She was 87. (Photo by Olivia Harris/Reuters)