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)

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)

Supporters of the presidential candidate Muhammadu Buhari and his All Progressive Congress hits with a motorbike another supporter during celebrations in Kano March 31, 2015. Nigeria's opposition APC declared an election victory on Tuesday for former military ruler Buhari and said Africa's most populous nation was witnessing history with its first democratic transfer of power. (Photo by Goran Tomasevic/Reuters)

A Chimpanzee is seen with funny expressions at Hanover Zoo on September 27, 2013 in Hanover, Germany. (Photo by Barcroft Media)

To mark Halloween, 150 teens descended upon a swimming pool in Essex to help mobile network giffgaff recreate the famous Tomatina tomato fight... only this time, with blood and guts. Different takes #giffgaffguts. On October 18, 2013 in Dagenham, England. (Photo by Dave J. Hogan/Stringer for giffgaff)

Visitors watch as Grigory Broverman, a member of the Cryophile winter swimmers club, pours a bucket of cold water over his 6-year-old daughter Liza during a flash mob, part of a celebration of Polar Bear Day at the Royev Ruchey Zoo in a suburb of the Siberian city of Krasnoyarsk, Russia, November 29, 2015. The air temperature was around minus 5 degrees Celsius. (Photo by Ilya Naymushin/Reuters)

Pakistani volunteers carry an injured passenger following a bomb blast in Peshawar, Pakistan, Wednesday, March 16, 2016. A bomb ripped through a bus carrying Pakistani government employees in the northwestern city of Peshawar on Wednesday, killing a number of people, police said. (Photo by Mohammad Sajjad/AP Photo)

A spinning top is seen on a hand during a performance at Sanxia old street in New Taipei City, Taiwan May 8, 2016. Taiwan's ancient folk art of spinning tops is kept alive by a group of enthusiasts who perform intricate tricks with the toys at a temple in Taipei, the capital. (Photo by Tyrone Siu/Reuters)