Iggy Azalea (L) and Ariana Grande perform onstage during the 2014 Billboard Music Awards held at MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Michael Tran/FilmMagic)

A festival goer uses a hula hoop, as revelers gather ahead of this weekends Glastonbury Festival of Music and Performing Arts on Worthy Farm in Somerset, southwest England, on June 25, 2014. US metal giants Metallica will play this year's coveted Saturday night headline spot at Britain's Glastonbury festival, organisers announced Thursday. It will be the “Master of Puppets” four-piece's first appearance at the legendary festival, held in south west England, following on from The Rolling Stones' Worthy Farm debut last year. (Photo by Leon Neal/AFP Photo)

Runners cross the Verrazano-Narrows Bridge shortly after the start of the New York City Marathon in New York, November 2, 2014. (Photo by Lucas Jackson/Reuters)

Miss California Crystal Lee performs during the Miss America 2014 pageant, Sunday, September 15, 2013, in Atlantic City, N.J. (Photo by Mel Evans/AP Photo)

Taylor Swift performs “All Too Well” at the 56th annual Grammy Awards at Staples Center. (Photo by Matt Sayles/Invision)

Julia Zlobina and Alexei Sitnikov of Azerbaijan gesture as they wait in the results area after competing in the ice dance free dance figure skating finals at the Iceberg Skating Palace during the 2014 Winter Olympics, Monday, February 17, 2014, in Sochi, Russia. (Photo by Vadim Ghirda/AP Photo)

Performers line up during the closing ceremony of the 2014 Winter Olympics, Sunday, February 23, 2014, in Sochi, Russia. (Photo by Darron Cummings/AP Photo)

“Catch of the Decade”. Can you guess what happened next? Photo location: Katmai National Park, Alaska, USA. (Photo and caption by Aaron Baggenstos/National Geographic Photo Contest)