Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)

A woman walks inside a building in downtown Havana, Cuba April 21, 2016. (Photo by Alexandre Meneghini/Reuters)

An internally displaced Afghan girl holds a child at a refugee camp in Kabul, Afghanistan May 31, 2016. (Photo by Mohammad Ismail/Reuters)

Second place, Nature: double trapping. Picture taken in the Brazilian Pantanal ... when I downloaded the CF did not want to believe it ... The nature knows we always give magnificent events but sometimes extraordinary. (Photo by Massimiliano Bencivenni/National Geographic Travel Photographer of the Year Contest)

Wrestlers perform at an all female wrestling event in London. England on August 17, 2017. (Photo by Neil Hall/Reuters)

The battle by Jose Garcia, US. Category: bird behaviour. A great white heron (Ardea herodias occidentalis) fighting a green snake in the Florida Everglades. The fight lasted for nearly 20 minutes with the heron having to release its prey. (Photo by Jose Garcia/2017 Bird Photographer of the Year Awards)

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)

Wild elephants, including a tusker (C), rummage through garbage dumped at an open ground in the village of Digampathana in north- central Sri Lanka on August 19, 2017. Sri Lanka has banned the dumping of garbage at open fields and near wildlife reserves, but the practice continues. (Photo by Lakruwan Wanniarachchi/AFP Photo)