Riot police walk past burning garbage containers during heavy clashes with demonstrators during a 24-hour strike on March 29, 2012 in Barcelona, Spain. Spanish workers staged a general strike to protest the government's latest labour reforms, which are designed to help Spain lower its deficit within EU limits. (Photo by David Ramos/Getty Images)

A picture made available on 14 July 2016 shows Greyhound dogs racing at the Wentworth Park Stadium in Sydney, New South Wales (NSW), Australia, 13 July 2016. Greyhound racing has returned to Sydney's Wentworth Park and other NSW tracks for the first time since the state government announced plans to ban it. NSW Premier Mike Baird announced last week plans to shut down the sport in NSW following a Special Commission of Inquiry report that found “chilling” evidence of systemic animal cruelty within the industry. (Photo by David Moir/EPA)

In this Thursday, December 1, 2016 photo, Cat Bigney, part of the Oglala Native American tribe, waits on the shore of the Cannonball river for travelers to arrive by canoe at the Oceti Sakowin camp where people have gathered to protest the Dakota Access oil pipeline in Cannon Ball, N.D. So far, those at the camp have shrugged off the heavy snow, icy winds and frigid temperatures. But if they defy next week's government deadline to abandon the camp, demonstrators know the real deep freeze lies ahead. Life-threatening wind chills and towering snow drifts could mean the greatest challenge is simple survival. (Photo by David Goldman/AP Photo)

Salt-resistant plants grow in sand made up of small fish bones on the shore of the Salton Sea before sunrise in an area where a controversial development would create a new town for nearly 40,000 people on the northwest shore of the biggest lake in California, the Salton Sea, on March 21, 2012 south of Mecca, California. (Photo by David McNew/Getty Images)

“The Boeing X-45 unmanned combat air vehicle is a concept demonstrator for a next generation of completely autonomous military aircraft, developed by Boeing's Phantom Works. Manufactured by Boeing Integrated Defense Systems, the X-45 was a part of DARPA's J-UCAS project”. – Wikipedia

Photo: Two X-45A Unmanned Combat Air Vehicles (UCAV) are shown to members of the news media July 11, 2002 at Edwards Air Force Base, California. The X-45A, developed by The Defense Advanced Research Projects Agency and the Boeing Company, is the first unmanned system designed from inception for combat missions. (Photo by David McNew/Getty Images)

Charlotte Roirdan, from Lyon and Turnbull, poses near portrait of a woman wearing a bikini made entirely out of postcards of the Queen on April 20, 2012 in Edinburgh, Scotland. The portrait Girl in a Yellow Bikini by David Mach, is estimated to raise between £4000 to £6000 at their Scottish Contemporary Sale to be held on April 25. (Photo by Jeff J. Mitchell)

A dog sits in a plastic tub filled with water in Taipei, Taiwan, 28 July 2020. Betel nut seller Mr Luo, the dog's owner, said he puts his dog, a 12-year-old mixed breed called Ah Dai (Stupid), in a plastic tub filled with water whenever the weather gets hot. Ah Dai enjoys the bath and can sit in the basin for hours, according to Mr Luo. Luo has a dozen pairs of glasses for Ah Dai, so the dog wears different glasses every day and many tourists take photos of Ah Dai. (Photo by David Chang/EPA/EFE)

Seljalandsfoss waterfall, located in Iceland. Seljalandsfoss is one of the most famous waterfalls of Iceland. This waterfall of the river Seljalandsá drops 60 metres (200 ft) over the cliffs of the former coastline. It's possible to go behind the waterfall. (Photo by HotSpot Media)