A mobile phone cover with a picture of Russian President Vladimir Putin and which reads “Mr President” is seen in this photo illustration taken a in hotel room in Kazan, Russia, July 30, 2015. He may be in charge of an economy in crisis, but if mobile phone covers and souvenir mugs are a barometer of popularity, Russian President Vladimir Putin need not fear for his political future. In fact, Moscow's annexation of Crimea from Ukraine last year has given the memorabilia makers even more material to glorify, sometimes wryly, a president whose image as a champion of Russian national interests in a hostile world is barely challenged in his own country. (Photo by Stefan Wermuth/Reuters)

Members of the Ukrainian Interior Ministry's special battalion Kiev-1 rescue a hostage, who was detained by a mock terroist, during an anti-terror drill in Kiev, Ukraine, August 28, 2015. (Photo by Valentyn Ogirenko/Reuters)

A protester jumps on the table in front of the European Central Bank President Mario Draghi during a news conference in Frankfurt, April 15, 2015. The news conference was disrupted on Wednesday when a woman in a black T-shirt jumped on the podium. (Photo by Kai Pfaffenbach/Reuters)

Students exercise in body training at Bishan Vocational Education Center in Chongqing, southwest China, January 13, 2016. These students were trained to be stewardesses of the high-speed train. (Photo by Xie Jie/Xinhua)

Tamberly Conway, bottom left, takes part in a large snowball fight in Dupont Circle on Sunday January 24, 2016 in Washington, DC. The Washington, DC area was blanketed by a large snow event. (Photo by Matt McClain/The Washington Post)

Four hundred buyers from around the world join 260 diamond manufacturing and trading firms on International Diamond Week as some 1,500 people are expected to trade more than billion of polished diamonds this week in Ramat Gan, Israel on February 16, 2016. The Israel Diamond Exchange is considered the most secure in the world, covering an area of 100,000 square meters with 3,500 bourse members. (Photo by Nir Alon via ZUMA Wire)

Rihanna and Drake perform at the BRIT Awards at the O2 arena in London, Britain, February 24, 2016. (Photo by Stefan Wermuth/Reuters)

The original costumes for Star Wars character Darth Vader stand on display at “Star Wars: The Exhibition” at County hall on May 04, 2007 in London, England. (Photo by MJ Kim/Getty Images)