Revelers dance during the “Ceu na Terra”, or Heaven on earth, carnival parade in Rio de Janeiro, Brazil, Saturday, February 7, 2015. Rio's over-the-top Carnival is the highlight of the year for many local residents. Hundreds of thousands of merrymakers are beginning to take to the streets in open-air “blocos” parties. (Photo by Felipe Dana/AP Photo)

Iranians flash the victory sign from their car while celebrating on a street in northern Tehran, Iran, Thursday, April 2, 2015, after Iran's nuclear agreement with world powers in Lausanne, Switzerland. The United States, Iran and five other world powers on Thursday announced an understanding outlining limits on Iran's nuclear program so it cannot lead to atomic weapons, directing negotiators toward achieving a comprehensive agreement within three months. (Photo by Ebrahim Noroozi/AP Photo)

A vendor smokes behind a display of dog meat at a dog meat market on the day of a local dog meat festival in Yulin, Guangxi Autonomous Region, June 22, 2015. (Photo by Kim Kyung-Hoon/Reuters)

A worker at the Jabal Saraj cement factory poses for a photograph in Jabal Saraj, north of Kabul, Afghanistan April 19, 2016. In an area desperately short of industry and jobs, local workers hope that the relaunch of the plant in Jabal Saraj, built by Czech engineers in 1957 and closed down by the Taliban in 1995, can show that Afghanistan's shattered industry can climb back to its feet after decades of war and destruction. But the outdated state-owned plant some 75 kilometres outside Kabul also shows how far it has to go before that promise can be achieved and there are serious questions over whether it has a viable future unless a new, modern facility is built to replace it. (Photo by Ahmad Masood/Reuters)

Metropolitan Transit Authority (MTA) Police Officer Keith Flood trains with his K-9 partner Doc, a German Shepherd, inside the “warehouse room” at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)

Stuart Craig of Washington tries out a Sig Sauer 1911 model Scorpion pistol at the Sig Sauer booth at the National Shooting Sports Foundation's 34th annual Shooting, Hunting, Outdoor Trade (SHOT) Show at the Sands Expo and Convention Center January 17, 2012 in Las Vegas, Nevada. The SHOT Show is the largest annual gathering of shooting professionals with more than 1,600 exhibitors and 30,000 attendees expected. (Photo by Ethan Miller/Getty Images)

In a 200-acre-plus dump 5 kilometers north of Haiti’s capital, Port-au-Prince, hundreds of men, women and children scavenge day and night through the burning wasteland. They earn $12 to $15 a day – on a good day – for recycling plastics as well as clothing, household items and aluminum (for smelting). Some 5,000 tons of waste is created each day in the Port-au-Prince area. (Photo and caption by Giles Clarke/Getty Images Reportage)

A Brazilian drug gang member nicknamed Pilintra, 26, poses with a gun atop a hill overlooking a slum in Salvador, Bahia State, April 11, 2013. One of Brazil's main tourist destinations and a 2014 World Cup host city, Salvador suffers from an unprecedented wave of violence with an increase of over 250% in the murder rate, according to the Brazilian Center for Latin American Studies (CEBELA). (Photo by Lunae Parracho/Reuters)