Khansa, an eight month old critically endangered Bornean orangutan shows off it's two front-teeth, at the Singapore Zoo on Thursday, January 11, 2018 in Singapore. The Singapore Zoo is active with its breeding programs as part of its wildlife preservation efforts. This is the Zoo's 46th successful orangutan birth. (Photo by Wong Maye-E/AP Photo)

Residents recently returning to their area cleared by government troops react as they ride a tricycle a day after President Rodrigo Duterte declared the liberation of Marawi city in southern Philippines Wednesday, October 18, 2017. Sporadic explosions continue Wednesday as Philippine soldiers fought to gain control of the last pocket of Marawi controlled by Islamic militants. (Photo by Bullit Marquez/AP Photo)

Children enjoy a sledge ride past ice swimming fans at the Zalew Zegrzynski lake in Nieporet, Poland, Sunday, February 25, 2018. A cold wave hit Poland with the temperature minus 8 degree Celsius (17.6 Fahrenheit) during the day and dropping to minus 16 degree Celsius (3.2 Fahrenheit) in the night in central Poland. (Photo by Alik Keplicz/AP Photo)

In this 2017 photo provided by Simon Pierce, Jonathan Green checks on a fin-mounted satellite tag on a whale shark in the Galapagos Islands area of Ecuador. Despite typically being bigger than a double-decker bus, the elusive whale shark has only tiny, almost useless teeth. It's also one of the least understood animals in the ocean. (Photo by Simonjpierce.com via AP Photo)

People cross Flagstaff Hill as the snow starts to fall, in Schenley Park, on their way to the Carnegie Mellon University campus, Tuesday, March 20, 2018, in the Oakland section of Pittsburgh. Yet another powerful storm bore down on the Northeast on Tuesday, with wind-whipped snow falling in parts of Pennsylvania and New Jersey as people grumbled and complained about a first day of spring that looked an awful lot like the last weeks of winter. (Photo by Darrell Sapp/Pittsburgh Post-Gazette via AP Photo)

A printed photograph taken on September 28, 2017 shows people bathing on the highway after Hurricane Maria destroyed people's homes, held up at the same spot of the highway where motorcyclists ride past in Naranjito, Puerto Rico, May 27, 2018. Thanks to the owners of the land alongside the highway, creek water was piped to the side of the road for people without water to use for bathing, washing clothes and dishes. (Photo by Ramon Espinosa/AP Photo)

People dressed as a dancing devils with giant mask dance on a street, during a traditional celebration in Naiguata, Venezuela, Thursday, May 31, 2018. Carrying in their hands striking masks mostly animals and sea monsters, hundreds of men, women and children went out to dance frantically as possessed by evil spirits in an ancient ritual known as Dancing Devils of Naiguata, the unorthodox way of the coastal towns of Venezuela to venerate God during the celebrations of Corpus Christi. (Photo by Ariana Cubillos/AP Photo)

Replicas of Joseph Stalin uniforms are offered to tourists who can rent them and wear them for a picture outside Stalin's bunker in Samara, Russia, on Tuesday, June 26, 2018. Stalin's secret WWII bunker has become the unlikely meeting point for thousands of cheerful fans who have arrived to the city during the World Cup days. (Photo by Luis Andres Henao/AP Photo)