Russian communists lay flowers at Soviet leader Joseph Stalin's tomb on Red Square next to the Kremlin wall in Moscow, Russia, December 21, 2015. Russian communists are marking the 136th anniversary of Josef Stalin's birthday. (Photo by Sergei Ilnitsky/EPA)

In this photo taken late Thursday, May 7, 2015, a prison guard, left, and seated inmates cast shadows on a wall while waiting for the beginning of a rock concert by Romanian band Pro Musica, inside the Popa Sapca jail in Timisoara, western Romania. (Photo by Adi Piclisan/AP Photo)

Gurung girls wearing traditional costumes dance while taking part in a New Year parade in Kathmandu, Nepal December 30, 2015. Members of the Gurung community in Nepal celebrate their Tamu Lhosar or Losar (New Year) with a feast and various cultural programs to usher in the year of the Monkey. (Photo by Navesh Chitrakar/Reuters)

People make pictures in a Soviet-era vintage subway car, with a Soviet railways emblem on the side of it, parked in the Partizanskaya subway station in Moscow, Russia, Friday, May 15, 2015. Vintage Soviet-era metro cars were exhibited at the Partizanskaya subway station as part of festivities marking the 80th anniversary of the Moscow subway on Friday. (Photo by Pavel Golovkin/AP Photo)

This Thursday, April 30, 2015 photo shows Lebanese citizens walking on the Corniche, or waterfront promenade in Beirut, Lebanon. This photo was shot through the lowered veil of a niqab, which is worn by some conservative Muslim women. The cloth allows women to follow a strict interpretation of their religious beliefs by preventing others from seeing their faces. (Photo by Hassan Ammar/AP Photo)

An actress performs in a puppet theater show at an UNRWA school in Burj al-Barajneh in Beirut May 14, 2015. The Arab Puppet Theatre Foundation (APTF) is touring the 68 schools of the UN refugee agency's UNRWA and performs for all 39,000 Palestinian students in Lebanon, in a project with UNICEF and UNRWA. (Photo by Mohamed Azakir/Reuters)

A Western Lowland Gorilla baby named “Mjukuu”, that was born in October last year, rides on the back of its Mother “Mbeli” in their enclosure at Taronga Zoo in Sydney, Australia, May 19, 2015. The baby gorilla was born six days ago, and is the second sired by the zoo's new Silverback, Kibali, who arrived from France in 2012. (Photo by David Gray/Reuters)

Women walk next to soldiers in Surcubamba, Peru, Thursday, May 21, 2015. The Joint Command of the Peruvian Armed Forces organized a humanitarian mission to Surcubamba, where health care was provided to families from nearby villages in this region called VRAEM, the acronym for Valley of the Apurimac, Ene and Mantaro rivers, where sixty percent of Peru's cocaine originates. (Photo by Rodrigo Abd/AP Photo)