Riot police scuffle with pro-democracy students after hundreds of protesters stormed into a restricted area at the government headquarters, after a rally ahead of the October 1 “Occupy Central” civil disobedience movement in Hong Kong September 27, 2014. Hong Kong riot police used pepper spray on Saturday to disperse dozens of students who had stormed government headquarters, but an equal number held their ground in protests against Beijing's tightening grip on the city. (Photo by Tyrone Siu/Reuters)

Yang Juan, an employee at Goopal Group, takes a nap in her seat after lunch, in Beijing, China, April 21, 2016. Office workers sleeping on the job is a common sight in China, where a surplus of cheap labour can lead to downtime at work. But in China's technology sector, where business is growing faster than many start-up firms can hire new staff, workers burn the midnight oil to meet deadlines and compete with their rivals. Some companies provide sleeping areas and beds for workers to rest during late nights. (Photo by Jason Lee/Reuters)

A man holds up for a picture a one hundred trillion Zimbabwean dollars note inside a shop in Harare, Zimbawe, June 12, 2015. Hyperinflation in Zimbabwe was a period of currency instability that began in the late 1990s shortly after the confiscation of private farms from landowners, towards the end of Zimbabwean involvement in the Second Congo War. During the height of inflation from 2008 to 2009, it was difficult to measure Zimbabwe's hyperinflation because the government of Zimbabwe stopped filing official inflation statistics. However, Zimbabwe's peak month of inflation is estimated at 79.6 billion percent in mid-November 2008. (Photo by Philimon Bulawayo/Reuters)

Two robotic legged squad support system (LS3) machines by the Defense Advanced Research Project Agency follow a technician during a demonstration at Joint Base Myer-Henderson Hall, Virginia, on September 10, 2012. (U.S. Marine Corps photo by Sgt. Mallory S. VanderSchans via The Atlantic)

Vehicles move past a man resting on a taxi, as he waits for passengers, along a road in Karachi, Pakistan, May 5, 2015. (Photo by Akhtar Soomro/Reuters)

A box of 36 coloured pencils as photographed in a studio with an illustrative price tag of $115 (US dollars), equivalent to the Bs. 725 (bolivars) that it costs on average to purchase in Caracas at the official exchange rate of 6.3 bolivars per dollar, in Caracas September 29, 2014. Venezuela's economic crisis has led to some shocking and surreal price distortions that hit people's buying power dramatically. (Photo by Carlos Garcia Rawlins/Reuters)

“For centuries, the Moken sea nomads have traveled the islands between Thailand and Myanmar fishing and foraging for food on the sea floor. Throughout the Mergui Archipelago, Moken migrate in flotillas of Kabangs (traditional boat of the Moken people), stopping at different islands and beaches. Expert freedivers, the Moken have adapted physically to an aquatic life, developing unique characteristics that let them see better and hold their breath longer while underwater”. – Taylor Weidman. Photo: Hook, an indigenous Moken man, holds a three-pronged throwing spear and searches for fish in the waters of Ko Surin National Park. March 1, 2013 – Ko Surin, Thailand. (Photo by Taylor Weidman/zReportage via ZUMA Press)

The northern lights, or aurora borealis, illuminate the sky over Flakstad beach on Lofoten Islands in the Arctic Circle on September 5, 2017. (Photo by Jonathan Nackstrand/AFP Photo)