Recording artist Ariana Grande performs onstage during the 2014 iHeartRadio Music Festival at the MGM Grand Garden Arena on September 19, 2014 in Las Vegas, Nevada. (Photo by Kevin Winter/Getty Images for iHeartMedia)

Trevor Olson, from Minnesota, dressed as the character “Joker”, poses for a photograph at New York's Comic Con convention, October 9, 2014, in New York City. The event draws thousands of costumed fans, panels of pop culture luminaries and features a sprawling floor of vendors in a space equivalent to more than three football fields in Javits Center. (Photo by Shannon Stapleton/Reuters)

“A Mothers Tail”. A baby cub pulls on his mother's tail to get attention. Photo location: Masai Mara, Kenya. (Photo and caption by Tori Marsh/National Geographic Photo Contest)

“Zeybeks”. That's Dance, Sunward and Zeybeks. (Photo by Hasan Baglar/2014 Sony World Photography Awards)

“Just hanging out”. As full autumn hits the valley of Hallingdal in Norway, this bear chills out in a tree which seems to barely cover its weight. Photo location: Flå, Hallingdal, Norway. (Photo and caption by Jorgen Tharaldsen/National Geographic Photo Contest)

“Slow”. A calm cow in the messy streets of Jodhpur. Photo location: India. (Photo and caption by Matthias Troeger/National Geographic Photo Contest)

“The Challenge!” Young boy relishes in a game of tug of war before school. Photo location: Lake Titicaca, Peru. (Photo and caption by Paul Heyman/National Geographic Photo Contest)

Ghanaian fans take a selfie prior to a Group G football match between Germany and Ghana at the Castelao Stadium in Fortaleza during the 2014 FIFA World Cup on June 21, 2014. (Photo by Patrik Stollarz/AFP Photo)