Tong Jieping, 44-year-old mentally disabled patient, is chained by his foot inside his room, in Qunxing village of Wangjiang county, Anhui province, China, July 14, 2015. Tong was diagnosed mentally ill when he was in his 20s. His parents, both in their 70s, could not afford the medical treatments so they had to lock him up in chains to prevent him from running away, according to Tong's family. (Photo by Reuters/Stringer)

A young couple rest in a football field after a forest fire devastated Santa Olga, 240 kilometres south of Santiago, on January 26, 2017. Six people – among them four firefighters and two police – have now been killed battling vast forest fires in central Chile, officials said Wednesday. Multiple blazes have ravaged 238,000 hectares (588,000 acres) and are growing, the National Forestry Corporation said in a statement. (Photo by Pablo Vera Lisperguer/AFP Photo)

A SpaceX Falcon Heavy rocket lifts off from historic launch pad 39-A at the Kennedy Space Center in Cape Canaveral, Florida, February 6, 2018. The world' s most powerful rocket, SpaceX' s Falcon Heavy, blasted off Tuesday on its highly anticipated maiden test flight, carrying CEO Elon Musk' s cherry red Tesla roadster to an orbit near Mars. Screams and cheers erupted at Cape Canaveral, Florida as the massive rocket fired its 27 engines and rumbled into the blue sky over the same NASA launchpad that served as a base for the US missions to Moon four decades ago. (Photo by Thom Baur/Reuters)

An Indian Sikh Nihang (a traditional Sikh religious warrior) Baba 'Avtar' Singh wears an oversized giant traditional turban as he pay respects at the Golden temple in Amritsar on November 10, 2015 on the eve of the Indian festival of Diwali, the festival of lights. There will be no spectacular show of light and fireworks this Diwali at the Golden Temple as the Shiromani Gurdwara Parbandhak Committee (SGPC) has decided not to celebrate the festival in the wake of series of incidents of alleged desecration of the Guru Granth Sahib (Sikh holy book). (Photo by Narinder Nanu/AFP Photo)

Attendants prepare to fill glasses for delegates before the opening session of the Chinese People's Political Consultative Conference at Beijing's Great Hall of the People, Thursday, March 3, 2016. The more than 2,000 members of China's top legislative advisory body convened their annual meeting Thursday, kicking off a political high season that will continue with the opening of the national congress on Saturday. (Photo by Mark Schiefelbein/AP Photo)

A man passes by an unfinished street art graffiti made in a stairway by French street artists Zag and Sia in Paris on March 1, 2016. The two artists drew inspiration from famous “Liberty Leading the People” (La Liberte guidant le peuple) painting by French Eugene Delacroix commemorating the July Revolution of 1830 and viewed as a symbol of the French Republic. (Photo by Joel Saget/AFP Photo)

At the dead of night, the photographer – known to his Instagram followers as Dark Cyanide – heads out to look for hidden gems, like abandoned stations, provisions and tunnels. His intriguing images feature vibrant streaks, graffiti, and tight framing – and by adding individuals to some to some of shots, he is also able to depict the incredible scale of some of the tunnels. Here: Unnamed subway track in New York City. (Photo by Dark Cyanide/Caters News)

This picture taken on February 23, 2014 shows participants wearing dresses running half-naked in the annual 3.5 km Undie Run held in the Olympic Forest Park smog-covered Beijing. Some 200 participants took part in this event, many of them with gas masks, as dangerous smog blighted swathes of northern China in recent days. (Photo by AFP Photo/STR)