Chinese women ride a bicycle together on a street September 10, 2014 in Beijing, China. (Photo by Kevin Frayer/Getty Images)

Ukrainian servicemen sit atop an armored personnel carrier (APC) at a military base in the town of Kramatorsk, eastern Ukraine, December 24, 2014. (Photo by Valentyn Ogirenko/Reuters)

A Sadhu or a Hindu holy man offers prayers while sitting inside a circle of burning “Upale” (or dried cow dung cakes) on the occasion to mark the Basant or spring festival, on the banks of river Ganga in the northern Indian city of Allahabad January 24, 2015. Basant is celebrated mainly in the northern Indian states marking the start of the spring season. (Photo by Jitendra Prakash/Reuters)

Soldiers stop to buy goods at the main market of Diffa, Niger, March 23, 2015. Diffa is where Nigerien and Chadian troops fighting insurgent group Boko Haram are based at. (Photo by Joe Penney/Reuters)

A Ukrainian woman begs Ukrainian President Petro Poroshenko to stop the bombing in Donetsk after shell hit the residential area where she lives, killing two civilians in Donetsk's Kyibishevsky district, on January 29, 2015. (Photo by Manu Brabo/AFP Photo)

Employees of the Park Royal resort wait for a shuttle to take them to work early in the morning on April 2, 2015 in Acapulco, Mexico. Despite problems with cartel violence Semana Santa is one of the biggest tourist weeks of the year in Acapulco, a city whose entire economy depends on tourism, and officials expect around 350,000 mostly Mexican visitors this week. (Photo by Jonathan Levinson/The Washington Post)

In this photo released by Xhinhua News Agency, a rescuer evacuates residents near the site of a chemical plant blast in Zhangzhou, southeast China's Fujian Province Tuesday, April 7, 2015. Six people have been hospitalized and hundreds of firefighters deployed to battle a blaze sparked by an explosion at Goure PX Plant that produces the toxic chemical paraxylene, officials said Tuesday. (Photo by Wei Peiquan/AP Photo/Xinhua)

A man rides a horse at a playground on a hill in Kabul April 19, 2015. (Photo by Mohammad Ismail/Reuters)