Fighters of the Free Syrian Army fire an anti-aircraft weapon in the rebel-held Mashhad area in southeastern Aleppo, on December 12, 2016, as they battle Syrian government forces during an operation to retake the embattled city. The crucial battle for Aleppo entered its “final phase” after Syrian rebels retreated into a small pocket of their former bastion in the face of new army advances. The retreat leaves opposition fighters confined to just a handful of neighbourhoods in southeast Aleppo, the largest of them Sukkari and Mashhad. (Photo by AFP Photo/Stringer)

“Hippo Chase”. As we approached the camp the Selinda Reserve of northern Botswana our boat passed by a hippo resting in the water. I turned around to look back at the boat's wake and saw the hippo charging after us! The hippo must've been tired from an all-nighter because he was angry. He rose way up out of the water three times trying to chase our boat! He was coming at us with such force that he created a wake of his own. Photo location: Selinda Reserve of northern Botswana. (Photo and caption by Curtis Simmons/National Geographic Photo Contest)

Firefighters pull a pig as they try to rescue it from a well at a pig farm in Huanghua township of Leqing, Zhejiang province, April 25, 2014. Seven local firefighters successfully rescued a 300 kg (661 lbs) pig which fell down a well on Friday morning, local media reported. (Photo by Reuters/China Daily)

In this October 24, 2010 file photo, Canadian-born actress Pamela Anderson poses for photographers during a photocall to unveil a new advertisement in aid of People for the Ethical Treatment of Animals (PETA) in London to encourage people to go vegetarian. PETA turns 35 years old in 2015, is the largest animal rights group in world with 3 million members, and has done a lot with a little s*x, shock and celebrity. (Photo by Akira Suemori/AP Photo)

Two models sit in an acrylic “ZF-Car” from the German manufacturer of the same name at the Automechanika automotive service industry trade fair in Frankfurt am Main, Germany, 12 September 2016. The Automechanika Fair runs from 13 to 17 September 2016. (Photo by Boris Rössler/EPA)

A picture made available on 21 July 2016 shows a visitor having a meal from a toilet bowl at “Jamban Cafe” (lit. Toilet Cafe) in Semarang, Central Java, Indonesia, 16 July 2016. The cafe was created by a sanitation expert for education purposes to stress the importance of using a dedicated toilet and keeping it clean to prevent disease. (Photo by EPA/Purwanto)

Caoimhe Cooburn-Gray poses for a picture on St. Patrick's day in Dublin, Ireland March 17, 2016. Saint Patrick's Day is a cultural and religious celebration held on 17 March, the traditional death date of Saint Patrick (c. AD 385–461), the foremost patron saint of Ireland. Celebrations generally involve public parades and festivals, céilithe, and the wearing of shamrocks, as well as green or orange attire. (Photo by Clodagh Kilcoyne/Reuters)

Shane Baker of Minnesota poses for a photo with adult film actress Rachel Starr at the Pornhub booth at the 2017 AVN Adult Entertainment Expo at the Hard Rock Hotel & Casino on January 18, 2017 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)