Mara Salvatrucha (MS) gang members show off their weapons in the Las Victorias district of San Salvador. In March 2012, the two largest gangs in El Salvador - the Mara Salvatrucha (MS) and the Barrio 18 (M18) - agreed on a truce following secret negotiations between gang leaders in prison which were mediated by a bishop and a former rebel leader. It is unclear whether the decision was the idea of the gangs themselves or whether they were encouraged by the government. (Photo by Adam Hinton)

White whales and their trainers present a show for visitors at Harbin Pole Aquarium on January 7, 2014 in Harbin, China. Aquarium is one of the tourist highlights of Harbin, attract domestic and foreign tourists visit each year. (Photo by Lintao Zhang/Getty Images)

Children are engulfed by foam during the Bubble Show event in Beijing, China, Sunday, June 26, 2016. Thousands of residents enjoy colored foam churned out by machines along a running track at the event designed for children and parents' interaction. (Photo by Ng Han Guan/AP Photo)

A picture made available on 21 July 2016 shows a visitor having a meal from a toilet bowl at “Jamban Cafe” (lit. Toilet Cafe) in Semarang, Central Java, Indonesia, 16 July 2016. The cafe was created by a sanitation expert for education purposes to stress the importance of using a dedicated toilet and keeping it clean to prevent disease. (Photo by EPA/Purwanto)

A woman in a USA sash, who would help show U.S. President Barack Obama to his seat, waits with other women in traditional dress for the start of the ASEAN Summit gala dinner in Vientiane, Laos September 7, 2016. (Photo by Jonathan Ernst/Reuters)

A picture shows the blood stained floor of a kindergarten following reported shelling in the rebel-held area of Harasta, on the northeastern outskirts of the capital Damascus, on November 6, 2016. At least four children were killed and 19 people injured in the government strike in Harasta, according to the Syrian Observatory for Human Rights. (Photo by Sameer Al-Doumy/AFP Photo)

It is already one of the world’s most iconic cities, but this incredible collection shows how much Paris has changed over the course of the past century. The collection, by French photographer Julien Knez, shows Paris in the 1940s against a backdrop of how the same places look today. Knez says he put the striking collection together to celebrate the 71st anniversary of the city’s liberation from Nazi control in August 1944. Here: Soldiers outside the Hotel De Ville in the 1940s. (Photo by Julien Knez/Caters News)

These snaps show a pair of daredevil bikers performing gravity-defying stunts as they get covered from head to toe in brightly colored powder. The stunning action shots show the fearless duo perform nail-biting tricks on their BMX bikes as they get showered with the brilliantly colored powder. The amazing images were taken by Christoph Jorda, from Bavaria, Germany, with bikers Thomas Kaiser and Konstantin Ottner. Here: The biker with the holi powder behind whilst performing stunts. (Photo by Christoph Jorda/Caters News)