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 building burns after an explosion on 2nd Avenue on March 26, 2015 in New York City. The seven alarm fire drew firefighters from across the city. A number of injuries have been reported. (Photo by Andrew Burton/Getty Images)

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)

Artist Le Pustra and organiser Else Edelstahl pose for a picture at Simon Dach Strasse, a street filled with many bars, in Berlin, Germany, August 28, 2016. Else Edelstahl organises the party series “Boheme Sauvage”, in which people dress up in 1920s style, celebrating Berlin nightlife of a past era. (Photo by Hannibal Hanschke/Reuters)

A man holds up for a picture a one hundred trillion Zimbabwean dollars note inside a shop in Harare, Zimbawe, June 12, 2015. Hyperinflation in Zimbabwe was a period of currency instability that began in the late 1990s shortly after the confiscation of private farms from landowners, towards the end of Zimbabwean involvement in the Second Congo War. During the height of inflation from 2008 to 2009, it was difficult to measure Zimbabwe's hyperinflation because the government of Zimbabwe stopped filing official inflation statistics. However, Zimbabwe's peak month of inflation is estimated at 79.6 billion percent in mid-November 2008. (Photo by Philimon Bulawayo/Reuters)

The Thufa hill in Reykjavik, Friday, October 28, 2016. Parliamentary elections will be held in Iceland on October 29, 2016, more than 250,000 voters are called to elect the new parliament, 63 members of the Althing parliament. (Photo by Frank Augstein/AP Photo)

In this October 7, 2014, photo, Fredrick Brower, center, helps cut up a bowhead whale caught by Inupiat subsistence hunters on a field near Barrow, Alaska. Drawing on tradition, and keeping within the closely monitored Aboriginal subsistence whaling guidelines, a bowhead whale is carved and divided by a crew armed with knives and hooks, and then shared according to custom. (Photo by Gregory Bull/AP Photo)

In this photo taken Friday, September 4, 2015, tourists Sarah and John Scott from Worcester, England, take a step back as a male silverback mountain gorilla from the family of mountain gorillas named Amahoro, which means “peace” in the Rwandan language, unexpectedly steps out from the bush to cross their path in the dense forest on the slopes of Mount Bisoke volcano in Volcanoes National Park, northern Rwanda. Deep in Rwanda's steep-sloped forest, increasing numbers of tourists are heading to see the mountain gorillas, a subspecies whose total population is an estimated 900 and who also live in neighboring Uganda and Congo, fueling an industry seen as key to the welfare of the critically endangered species as well as Rwanda's economy. (Photo by Ben Curtis/AP Photo)