Young gymnasts practice pull-up on a bar at a gymnasium of a sports school in Jiaxing, Zhejiang province April 11, 2015. (Photo by William Hong/Reuters)

An Anti-Balaka fighter, member of a militia opposed to the Seleka rebel group, puts a knife to his throat showing what he would do to any Seleka, on the outskirts of the Boy-Rabe neighborhood in Bangui on December 14, 2013. France raised alarm on December 13 over worsening violence in the Central African Republic, as UN chief Ban Ki-moon urged warring Christians and Muslims to stop the bloodshed that has left more than 600 dead in the past week. (Photo by Ivan Lieman/AFP Photo)

A man prays to mourn victims of the March 11, 2011, earthquake and tsunami in front of a ship brought ashore by the disaster in Kesennuma, Miyagi Prefecture, Japan. (Photo by Kyodo via Reuters)

In this photo taken Sunday, May 6, 2012, Denis Lutskevich, left, is detained by police during an opposition rally in Bolotnaya Square in Moscow. The former naval cadet and first-year student, 21-year-old Lutskevich was attending his first protest when he was detained, and is still in prison Monday May 6, 2013, on the first year anniversary of the protest. (Photo by Pavel Golovkin/AP Photo)

Russian Police academy female cadets march during a rehearsal for the Victory Day military parade at Dvortsovaya (Palace) Square in St Petersburg, Russia, Wednesday, May 7, 2014. Victory Day, marking the defeat of Nazi Germany, is Russia's most important secular holiday celebrated on May 9. (Photo by Dmitry Lovetsky/AP Photo)

“Residents in a small town littered with giant potholes may be ready to “crack” the art world – after turning their massively damaged roads into hilarious masterpieces. Fun-natured drivers from Scranton, Pennsylvania have been challenged by an arts group to turn the ugly craters in their neighborhood into pothole art”. – Caters News. Photo: Cereal bowl pothole. (Photo by Caters News)

Tourists take a “selfie” as demonstrators burn a trash container during a May Day rally in Barcelona, Spain, on May 1, 2014. Tens of thousands of workers marked May Day in European cities with a mix of anger and gloom over austerity measures imposed by leaders trying to contain the eurozone's intractable debt crisis. (Photo by Manu Fernandez/Associated Press)