A street cleaner demonstrates his martial arts skills in front of a closed shop near Beijing's Tiananmen Square September 2, 2015 as the capital prepares for tomorrow's parade. (Photo by Damir Sagolj/Reuters)

People look at the Harmony of the Seas cruise ship leaving the STX shipyard of Saint-Nazaire, western France, for a three-day test offshore, on March 10, 2016. With a capacity of 6.296 passengers and 2.384 crew members, the Harmony of the Seas, built by STX France for the Royal Caribbean International, is the world's largest ship cruise. (Photo by Loic Venance/AFP Photo)

The second and final qualification motor (QM-2) test for the Space Launch System's booster, June 28, 2016, at Orbital ATK Propulsion Systems test facilities in Promontory, Utah. During the Space Launch System flight the boosters will provide more than 75 percent of the thrust needed to escape the gravitational pull of the Earth, the first step on NASA's Journey to Mars. (Photo by Bill Ingalls/NASA)

A woman whose livelihood depends on selling recyclable wastes collects trash from a dumping site while surrounded by Marabou storks on the outskirts of Uganda's capital Kampala March 31, 2015. (Photo by James Akena/Reuters)

A three-seater Toyota Kikai concept car is displayed during the 2016 CES trade show in Las Vegas, Nevada January 8, 2016. (Photo by Steve Marcus/Reuters)

Disguised revellers parade on the occasion of the Cortege during the Carnival in Basel, Switzerland, February 17, 2016. (Photo by Georgios Kefalas/EPA)

“I have seen batches of banknotes worth more than $2.6 million, but beyond all doubt, gold bars look much more attractive!”. – Shamil Zhumatov. Photo: Cooling-down gold ingot. March 14, 2013; Tien Shan mountains, Kyrgyzstan. (Photo by Shamil Zhumatov/Reuters)

The attendants of the Sumptha Raja, Agra Durbar. (Photo by Hulton Archive/Getty Images). 1873