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 man plays in front of a wave crashing into Beirut's Corniche, a seaside promenade, as high winds sweep through Lebanon ahead of an impending storm January 6, 2015. (Photo by Jamal Saidi/Reuters)

A serviceman walks near an APC while a helicopter flies on the position of the Ukrainian troops in Donetsk region on August 9, 2014. Fighting with pro-Russian separatists in eastern Ukraine has left 13 troops dead in the last 24 hours, Ukraine's military said Saturday. (Photo by Anatolii Stepanov/AFP Photo)

A woman reacts as she uses a selfie stick to take a photo of herself at Tiananmen Square in Beijing, China, Thursday, April 30, 2015. Selfie sticks are gaining popular in China, and many people are using them at popular tourist destinations. (Photo by Andy Wong/AP Photo)

Cave Diver, Anhumas Abyss, Bonito, Brazil: The Anhumas Abyss is an underground cavern with a crystal-clear lake below, more than 260 feet (79 m) deep. A visitor must enter through a narrow opening at the top of the chamber and rappel into the cave. Snorkeling and scuba diving in the lake reveal amazing scenery. Distinctive, conical limestone stalagmites and stalactites occupy the lake and the surrounding area, some reaching 65 feet (20 m) high. (Photo by Marcio Cabral/Nature’s Best Photography Awards 2017)

Local people check the growth of mussels at a river in Haian County on November 2, 2017 in Nantong, Jiangsu Province of China. Fish, shrimp, crab and mussel farming cleans the river and increases the villagers' income at Haian county in Jiangsu. (Photo by VCG/VCG via Getty Images)

Shoppers walk past crocodiles for sale at a market in Bata on February 3, 2015. Markets in Equatorial Guinea sell a variety of animals including pangolins, monkeys and crocodiles as food. (Photo by Carl de Souza/AFP Photo)

Two women kiss each other during a flashmob on the ocassion of the International Day Against Homophobia, Transphobia and Biphobia in Pamplona, Navarra, Spain, 17 May 2017. The International Day Against Homophobia, Transphobia and Biphobia is held every year on 17 May. (Photo by Villar Lopez/EPA/EFE)