Participants perform a dragon dance as they march during a lantern parade marking the start of a month- long “Lotus Lantern Festival” to celebrate the upcoming Buddha' s birthday, in Seoul on April 29, 2017 Buddha' s birthday falls on May 3. (Photo by Ed Jones/AFP Photo)

A police officer detains a woman on suspicion of collaborating with the 18th street gang during a "Safe House" operation at the Concepcion neighbourhood in San Salvador, July 2, 2015. Salvadoran police make “Safe House” operations at dangerous neighbourhoods of the capital to prevent murders, according to local media. (Photo by Jose Cabezas/Reuters)

People stroll alongside one of the hills of the Tio Pio park in Madrid, Monday, January 25, 2016. The park is a high viewpoint frequented mostly by locals due to its view of the Spanish capital skyline. (Photo by Francisco Seco/AP Photo)

A photograph of Cuba's former President Fidel Castro decorates a wall inside a state-run market in Havana, March 8, 2016. (Photo by Alexandre Meneghini/Reuters)

Subway passengers walk past bronze sculptures representing the Soviet people at the Ploshchad Revolyutsii metro station in Moscow, on November 14, 2012. The station was opened in 1938. (Photo by Kirill Kudryavtsev/AFP Photo)

An abandoned tank left by Boko Haram, February 20, 2016, seen on the road to Michika, Nigeria – a town formerly occupied by the insurgents. On April 14, 2014, 300 schoolgirls in the Chibok village in Nigeria were kidnapped by the terrorist group, Boko Haram. Two years later, the majority of these girls are still missing. According to the Global Terrorism Index Report 2015, Boko Haram, which operates mainly in Nigeria, has become the most deadly terrorist group in the world. (Photo by Danielle Villasana)

A scavenger sifts through garbage piled on the bank of Beirut river, Lebanon August 24, 2015. Lebanese protest organisers called for a fresh demonstration against the government on Saturday after two days of rallies that turned violent in central Beirut and wounded scores of people. The “You Stink” campaign has mobilised against the government's failure to solve a garbage disposal crisis, bringing thousands of people onto the streets in protests that have threatened the survival of the cabinet. (Photo by Mohamed Azakir/Reuters)

Students walk to school on the first day of their new school year in Giza, south of Cairo, Egypt September 25, 2016. (Photo by Mohamed Abd El Ghany/Reuters)