Participants take part in the Mud Day race, a 13km obstacle course, on March 24, 2017 in the Israeli Mediterranean coastal city of Tel Aviv. (Photo by Jack Guez/AFP Photo)

A woman sits on a terrace at Tiki hostel in Cantagalo favela, in Rio de Janeiro, Brazil, April 16, 2016. Hostels in a few of Rio's more than 1,000 slums serve not only as a cheap housing alternative for the more adventurous among the estimated 500,000 foreign tourists expected to arrive for the Olympics in August. The establishments also open up the rich culture of the city's shantytowns for travellers, giving them a glimpse into once “no-go” areas where about one-fifth of Rio's population lives. (Photo by Pilar Olivares/Reuters)

A person stands near the “Untitled” installation of miniature elevators by Maurizio Cattelan at a preview of the Postwar and Contemporary Art Evening Sale at Christie's auction house on November 4, 2011 in New York City. The 33-inch functioning elevator installation is expected to realize $400,000-$600,000 at the November 8 auction. (Photo by Mario Tama/Getty Images)

Odin, a five year-old White Bengal Tiger dives for a piece of meat thrown to him by a trainer during a big cat show at Six Flags Discovery Kingdom June 1, 2007 in Vallejo, California. Unlike most cats that are afraid of water, Odin loves diving in the pool to retrieve bits of meat fed to him by his trainers. (Photo by Justin Sullivan/Getty Images)

An Apple Inc., employee holds the new white iPhone 4 at the Apple store April 28, 2011 in Palo Alto, California. The long awaited white iPhone, first announced in June of 2010, went on sale worldwide for the first time today. (Photo by David Paul Morris/Getty Images)

A white Bengal tiger cub plays with its mother in a zoo in the Siberian city of Novosibirsk, about 2,800 kilometers (1,750 miles) east of Moscow, Russia, Tuesday, April 21, 2015. Two blue-eyed Bengal tiger cubs were born in March to a couple of white tigers at Novosibirsk zoo. (Photo by Ilnar Salakhiev/AP Photo)

A Tibetan rider fires his weapon as he perfoms his riding skills at the Qinghai Yushu Horse Racing Festival on July 27, 2007 in Yushu County of Yushu Tibetan Autonomous Prefecture, Qinghai Province, northwest China. The Horse Racing Festival of Tibetan nomads in Yushu Prefecture falls in late July and early August on the Tibetan calendar. During the festival, various equestrian skills will be performed along with singing, dancing and costume shows. (Photo by China Photos/Getty Images)

In this Friday, March 13, 2015, Mitch Seavey's lead dogs with frosty whiskers at the Huslia, Alaska, checkpoint for the Iditarod Trail Sled Dog Race. (Photo by Loren Holmes/AP Photo/Alaska Dispatch News)