In this May 4, 2014 photo, a miner holds an amalgam of mercury and gold he mined after working a 28-hour shift at an illegal gold mining process, in La Pampa, in Peru's Madre de Dios region. Thousands of artisanal gold miners sweat through the long shifts and endure, for a few grams of gold, the perils of collapsing earth, limb-crushing machinery and the toxic mercury used to bind gold flecks. (Photo by Rodrigo Abd/AP Photo)

A Raramuris indigenous woman takes part in the “Ultra maraton de los Canones 2017” (Ultra marathon of the Canyons), at La Sinforosa Canyon, in Guachochi, Chihuahua state, Mexico on July 15, 2017. More than 600 participants from different countries take part in the 63 and 100 kilometers races, along the Tarahumara mountain range. (Photo by Herika Martinez/AFP Photo)

A street artist dances tango in Buenos Aires, Argentina, Tuesday, January 20, 2015. Tango is a partner dance that originated in the 1890's along the Rio de la Plata, the border between Uruguay and Argentina. UNESCO approved in 2009, a joint proposal by the two nations to include the dance in its Intangible Cultural Heritage List. (Photo by Rodrigo Abd/AP Photo)

In this two photo combination picture, the Eiffel Tower with its usual lighting at left, and after the lighting was switched off at right, at the occasion of the Earth Hour, in Paris, France, Saturday March 28, 2015. This Saturday, 28 March 8:30 p.m. local time, individuals, businesses, cities and landmarks around the world are switching off their lights for one hour to focus attention on climate change. (Photo by Remy de la Mauviniere/AP Photo)

A woman reacts after she was hit with pepper spray deployed by police as they cleared a street with protesters rallying against a new national security law in Hong Kong on July 1, 2020, on the 23rd anniversary of the city's handover from Britain to China. A man found in possession of a Hong Kong independence flag became the first person to be arrested under Beijing's new national security law for the city, police said on July 1. (Photo by Dale De La Rey/AFP Photo)

Chelsea Hughes, 25, sings at the first annual Underwear Karaoke, an event that pairs two common fears: being seen in your underwear and singing in public, in Los Angeles, California March 12, 2015. (Photo by Lucy Nicholson/Reuters)

Lukas Michul, a member of the “dream walker” group jumps from atop the rugged rocks overlooking the azure waters of Navagio beach, one of the Greece's most renowned leisure spots on the popular tourist island of Zakynthos on June 23, 2014. This is rope jumping – part diving, part rock climbing, with a touch of engineering. The aim of the project is to dream jump in 80 places with most ravishing nature and architecture all over the world .They plan to stage their next leaps at a cave complex in Croatia, a French viaduct, skyscrapers in Las Vegas and Johannesburg, and the Grand Canyon. (Photo by Louisa Gouliamaki/AFP Photo)

Filipinos cross a swelling river in Las Pinas city, south of Manila, Philippines, 09 July 2015. According to the Philippines State weather forecast, heavy rainfall is expected in Metro Manila and nearby provinces due to an enhanced Southwest Monsoon and Tropical Storm Linfa, Typhoon Chan-hom and Typhoon Nangka which are lining up across the Pacific Ocean. (Photo by Francis R. Malasig/EPA)