Russian army soldiers, dressed in WWII era uniforms, march along the Red Square during a general rehearsal for the Victory Day military parade which will take place at Moscow's Red Square on May 9 to celebrate 70 years after the victory in WWII, in Moscow, Russia, Thursday, May 7, 2015. (Photo by Ivan Sekretarev/AP Photo)

Singer Katy Perry arrives at the Metropolitan Museum of Art Costume Institute Gala 2015 celebrating the opening of “China: Through the Looking Glass” in Manhattan, New York May 4, 2015. (Photo by Lucas Jackson/Reuters)

A pro-Russian rebel guards a captured former Ukrainian Army checkpoint outside Vuhlehirsk, Donetsk region, eastern Ukraine, Thursday, February 5, 2015. The rebels have closed in around the town in a strategy they triumphantly refer to as the Debaltseve cauldron. Separatists recently burst through government lines in the rural settlement of Vuhlehirsk. (Photo by Vadim Braydov/AP Photo)