The disused bobsled track from the Sarajevo 1984 Winter Olympics is seen on Mount Trebevic, near Sarajevo, September 19, 2013. Abandoned and left to crumble into oblivion, most of the 1984 Winter Olympic venues in Bosnia's capital Sarajevo have been reduced to rubble by neglect as much as the 1990s conflict that tore apart the former Yugoslavia. (Photo by Dado Ruvic/Reuters)

Brave slackliners have been pictured walking the ropes above Rio de Janeiro, Brazil on August 15, 2016, with the half a mile drop showing the city in all its glory. The stunning shots show the daredevils tread across an eighty-two-foot-long high line on Pedra da Gvea mountain with an amazing sunrise illuminating the city landscape behind. (Photo by Rafael Moura/Caters News Agency)

Indian mourners perform a cremation on the roof of a building overlooking The Manikarnika Ghat in Varanasi on August 23, 2016. India's holy city of Varanasi has been forced to halt cremations along the banks of the sacred river Ganges as deadly floods from monsoon rains hit parts of the country, an official said. More than 100,000 people have been forced from their homes in recent days in northern Uttar Pradesh and neighbouring Bihar states as rain-swollen rivers burst their banks. (Photo by Sanjay Kanojia/AFP Photo)

In this Friday, January 7, 2011 photo, people carry baskets of coal scavenged illegally at an open-cast mine in the village of Bokapahari in the eastern Indian state of Jharkhand where a community of coal scavengers live and work. The world's biggest coal users – China, the United States and India – have boosted coal mining in 2017, in an abrupt departure from last year's record global decline for the heavily polluting fuel and a setback to efforts to rein in climate change emissions. (Photo by Kevin Frayer/AP Photo)

Police officers laugh as Greenpeace activists create a burnt smoldering rain-forest with a lifelike animatronic orangutan at the headquarters of Oreo cookies, in protest over their use of palm oil on November 19, 2018 in Uxbridge, England. Greenpeace is calling on the makers of Oreo to stop buying palm oil from Wilmar, the largest palm oil producer, who they say have destroyed 70,000 hectares of Indonesian rain forest in the last two years. (Photo by Chris J. Ratcliffe for Greenpeace via Getty Images)

A monkey catches knives as it balances on a board during a daily training session at a monkey farm in Baowan village, Xinye county of China's central Henan province, February 2, 2016. Baowan village of China's central Henan province appears to be your average farming community from the surface, but at a closer look, one can hear monkey hoots from every direction. Although no official number exists, villagers say that they have been a breeding ground for both monkeys and monkey trainers for centuries. (Photo by Jason Lee/Reuters)

Indonesian mahouts (elephant masters) bathe elephants prior to a daily patrol at a Conservation Respons Unite (CRU) to control elephant-human conflicts in Serbajadi, East Aceh on April 7, 2016. Elephants have joined the front line in the fight against poaching and illegal logging in the dense jungles of Sumatra. Guided by their Indonesian mahouts, they trek alongside rivers, over rough terrain and deep into the rainforest in an area that is home to numerous endangered species, from orangutans to tigers, but which has suffered devastating deforestation in recent years. (Photo by AFP Photo/Januar)

Schoolchildren play music to entertain and inspire people on their way home from work Tuesday, March 29, 2016 in Pyongyang, North Korea. North Korea has called a 70-day loyalty drive areas of a major congress of the ruling party scheduled for early May and everyone from students to coal miners have been mobilized nationwide to demonstrate their devotion to the leadership. (Photo by Eric Talmadge/AP Photo)