Singer Rihanna performs onstage during the 2011 Billboard Music Awards at the MGM Grand Garden Arena May 22, 2011 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images for ABC)

Actors Justin Timberlake (L) and Mila Kunis present an award onstage during the 2011 MTV Movie Awards at Universal Studios' Gibson Amphitheatre on June 5, 2011 in Universal City, California. (Photo by Kevin Winter/Getty Images)

A fan lies passed out on the first day of the Wacken Open Air heavy metal music fest on August 4, 2011 in Wacken, Germany. Approximately 75,000 heavy metal fans from all over the world have descended on the north German village of 1,800 residents for the annual three-day fest. (Photo by Sean Gallup/Getty Images)

An Egyptian university student drives a hybrid racing car he built with his team to compete at the Global Hybrid-Electric Challenge in Cairo, Egypt September 2, 2016. (Photo by Mohamed Abd El Ghany/Reuters)

A model poses backstage during the Speedo show as part of Mercedes Benz Fashion Festival Sydney 2011 at Sydney Town Hall on August 24, 2011 in Sydney, Australia. (Photo by Stefan Gosatti/Getty Images)

In this Wednesday, March 18, 2015 photo, limestone quarry workers walk through a cloud of dust spewed into the air by rotor blades of the stone-cutting machinery in the desert of Minya, southern Egypt. Around 45,000 people, including children, work in an estimated 1,500 quarries, digging out stones that later will be used in construction or powdered to be used by pharmaceutical and ceramic companies. (Photo by Mosa'ab Elshamy/AP Photo)

Mohamed Mostafa, 35, carries dyed yarns at a dye workshop in old Cairo, Egypt, March 17, 2016. Egypt's hard currency crisis and competition from modern factories in Asia and at home threaten one of the last dye workshops in Egypt. But one of its owners takes comfort in the trade's ancient resilience. Mohamed Mostafa boasts that the profession dates back 3,000 years, so it can survive anything. (Photo by Amr Abdallah Dalsh/Reuters)

Carlos Boozer #5 of the Chicago Bulls grabs a rebound next to David West #30 of the New Orleans Hornets at the United Center on March 7, 2011 in Chicago, Illinois. The Bulls defeated the Hornets 85-77.