A visitor takes in a view of the downtown district from Twin Peaks on Friday, January 9, 2015, in San Francisco. (Photo by Marcio Jose Sanchez/AP Photo)

A Hindu devotee girl stands after getting her tongue pierced with a metal rod during the Thaipusam festival in Kuala Lumpur, Malaysia, Tuesday, February 3, 2015. Thaipusam, which is celebrated in honor of Hindu god Lord Murugan, is an annual procession by Hindu devotees seeking blessings, fulfilling vows and offering thanks. (Photo by Joshua Paul/AP Photo)

Ty, a 15-year-old boy, poses for a picture while collecting usable items at a landfill dumpsite outside Siem Reap March 19, 2015. Ty, who finished six-grade primary school, said he makes 5 USD per month working at the dumpsite. (Photo by Athit Perawongmetha/Reuters)

Handout photo dated March 20, 2015 issued by Chester Zoo of lemurs looking at the eclipse over Chester Zoo. (Photo by Steve Rawlins/PA Wire/Chester Zoo)

A man rows a boat on the Dal Lake as a woman holds an umbrella during snowfall in Srinagar February 19, 2015. (Photo by Danish Ismail/Reuters)

A motorcyclist dodges in the annual water-splashing festival to mark the New Year of the Dai minority in Menglian, Yunnan province April 13, 2015. (Photo by Wong Campion/Reuters)

A Uyghur boy sits atop a horse as he has his picture taken outside the Id Kah Mosque before the Eid holiday on July 28, 2014 in old Kashgar, Xinjiang Province, China. Nearly 100 people have been killed in unrest in the restive Xinjiang Province in the last week in what authorities say is terrorism but advocacy groups claim is a result of a government crackdown to silence opposition to its policies. China's Muslim Uyghur ethnic group faces cultural and religious restrictions by the Chinese government. Beijing says it is investing heavily in the Xinjiang region but Uyghurs are increasingly dissatisfied with the influx of Han Chinese and uneven economic development. (Photo by Kevin Frayer/Getty Images)

People ride a Ferris wheel as fireworks illuminate the sky over Edinburgh, Scotland. (Photo by David Cheskin/Press Association)