“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)

Spectators cheer as the United Launch Alliance Delta 4-Heavy rocket, with NASA's Orion spacecraft mounted atop, lifts off from the Air Force Station, December 5, 2014, in Cape Canaveral, Fla. (Photo by Smiley N. Pool/AP Photo/Houston Chronicle)

Liu Chunxia, a supporter of Xu Zhiyong, one of China's most prominent rights advocates, is detained by policemen while she gathers with other supporters nearby a court where Xu's trial is being held in Beijing January 22, 2014. When dozens of activists unfurled banners across the country last March and April calling for officials to disclose their assets, they did so at the urging of one of China's most prominent rights advocates, Xu Zhiyong. Xu, 40, stands trial on Wednesday on a charge of “gathering a crowd to disturb public order” punishable by up to five years in prison. His case will almost certainly spark fresh criticism from Western governments over Beijing's crackdown on dissent. (Photo by Kim Kyung-Hoon/Reuters)

A hairdressing mannequin is seen outside a hair salon amid as Typhoon Matmo hits Nantong, Jiangsu province July 25, 2014. Matmo, which made landfall in Fujian Province on Wednesday, has brought strong winds and heavy downpours to more areas in China after it moved northward on Thursday, Xinhua News Agency reported. (Photo by Reuters/Stringer)

“The Tonight Show” host Jimmy Fallon, center, exits the water during the Chicago Polar Plunge, Sunday, March 2, 2014, in Chicago. Fallon joined Chicago Mayor Rahm Emanuel in the event. (Photo by Andrew A. Nelles/AP Photo)

Undated handout photo of Buckbeak, a Hippogriff that lived with Rubeus Hagrid in the Harry Potter series, has his feathers preened and replenished by featherologist Val Jones, as he will feature in the the Feathers and Flight event at Warner Bros. Studio Tour London. This is the first make-over Buckbeak has received since the hugely popular Harry Potter film series was made. His intricate coat is created from thousands of individually airbrushed chicken and goose feathers that Val will carefully clean and replenish in time for the start of Feathers and Flight. Val will lead an expert team to demonstrate the techniques that made winged wonders such as Buckbeak and Fawkes the Phoenix a reality on screen. (Photo by Tim Anderson/PA Wire)

“One in Eight Hundred” by Mario Wezel, from Germany, is the winner of the “People” category. The title refers to the odds given to Martin and Karina at their prenatal screening before their daughter, Emmy, was born. The five-year-old from Denmark has Down's Syndrome. (Photo by Mario Wezel/Sony World Photography Awards)

Andrea Petkovic of Germany in action against Sara Errani of Italy during day one of the Mutua Madrid Open tennis tournament at the Caja Magica on May 3, 2014 in Madrid, Spain. (Photo by Julian Finney/Getty Images)