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)

Children play on an abandoned car near a protest, which is against the dissolution of Yemen's parliament and the Shi'ite Muslim Houthi militia's tightening grip on power, in the southwestern city of Taiz, February 13, 2015. (Photo by Mohamed al-Sayaghi/Reuters)

Marine biologist Simon Pierce, who studies whale sharks, happened to be in the right place at the right time to capture amazing photo off Cancun, Mexico. (Photo by Simon Pierce/Mercury Press/Caters News)

Onlookers gather around a struggling beached whale in the Yoff neighborhood of Dakar, Senegal Wednesday, May 21, 2008. Residents worked Wednesday morning to save some of the more than 80 whales that were stranded on the beach Tuesday night. This whale was successfully towed out to sea by a fishing boat, though at least 20 others lay dead on the beach by midday Wednesday. (Photo by Rebecca Blackwell/AP Photo)

Geisha women parade down the street to Asakusa Shrine in the compound of Sensoji Temple Friday, May 19, 2017, in Tokyo prior to the annual Sanja Festival, one of the three major festivals in Tokyo. (Photo by Eugene Hoshiko/AP Photo)

The lead singer of one band talks to two bemused kids at a gig at the “Warzone Centre” in Belfast, Northern Ireland, 1980s. (Photo by Ricky Adam/Mediadrumworld)

Palestinian man Mohammed al-Hoor, 23, demonstrates his street workout skills in Nuseirat refugee camp, in the central Gaza Strip on May 2, 2017. (Photo by Mohammed Salem/Reuters)

Lava cascades down the slopes of Mayon volcano as seen from Legazpi city, Albay province, around 340 kilometers (210 miles) southeast of Manila, Philippines, Monday, January 15, 2018. More than 9,000 people have evacuated the area around the Philippines' most active volcano as lava flowed down its crater Monday in a gentle eruption that scientists warned could turn explosive. (Photo by Earl Recamunda/AP Photo)