A South Sudanese People Liberation Army (SPLA) soldier patrols the streets in Malakal on January 21, 2014. (Photo by Harrison Ngethi/AFP Photo)

Model Olivia Culpo (L) and host Nick Jonas, after getting slimed, backstage during Nickelodeon's 28th Annual Kids' Choice Awards held at The Forum on March 28, 2015 in Inglewood, California. (Photo by Lester Cohen/KCA2015/WireImage)

A woman crowd-surfs in front of the main stage at the Woodstock Festival in Kostrzyn-upon-Odra, close to the Polish-German border, August 2, 2014. Some 500 thousand people attended the festival that is the brainchild of Polish journalist and social campaigner Jerzy Owsiak. He initiated the event to say thank you to those who donated money to his GOCC charity organisation that delivers medical care for children. (Photo by Thomas Peter/Reuters)

Socialite Kathy Hilton attends the Prudential Financial Grand Prix Hamptons Classic Horse Show August 31, 2003 in Bridgehampton, New York.

Colonel Roscoe Turner, the pilot of an American Boeing plane, showing his wife a model of the plane, at the airfield in Mildenhall. (Photo by R. Wesley/Fox Photos/Getty Images). 19th October 1934

Regina Halmich and Sergiy Plyuta perform during the 'Let's Dance' TV show at Coloneum on March 23, 2011 in Cologne, Germany.

Parked scooters and motorcycles in a line on January 13, 2012 in London, England. Statistics showed a 12% increase in scooter registration in 2011, with cost savings on petrol, parking and congestion charge (in London) believed to be the primary factor. (Photo by Matthew Lloyd/Getty Images)