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)

Handguns turned in from the public as part of the “Gun Turn-in” event where a $100 gift card is given for every firearm and a $10 gift card for each BB-gun, air-gun, or replica firearm turned over to police at Universal Missionary Baptist Church in Chicago, Illinois, U.S. May 28, 2016. (Photo by Jim Young/Reuters)

Dressed a Royal Canadian Mounted Police officer, Stephane Delage carries a Canadian flag while on stilts as he entertains the crowd during Canada Day festivities in Vancouver, B.C., on Monday, July 1, 2013. (Photo by Darryl Dyck/The Canadian Press)

Lady Gaga performs at Staples Center on August 11, 2010 in Los Angeles, California. (Photo by Jason Merritt/Getty Images)

Austrian Bodybuilder and actor Arnold Schwarzenegger has some fun at a party on a yacht in Marina Del Rey in September 1979 in Los Angeles, California. (Photo by Michael Ochs Archives/Getty Images)

Michelle Rodriguez attends the 2016 Vanity Fair Oscar Party Hosted By Graydon Carter at Wallis Annenberg Center for the Performing Arts on February 28, 2016 in Beverly Hills, California. (Photo by Karwai Tang/WireImage)

Kenyan riot police officers raise batons over a man during a demonstration of Kenya's opposition supporters in Nairobi, on May 16, 2016. Opposition protestors led by former Prime Minister Raila Odinga gathered outside the Indepedent Electoral and Boundaries Comission building to demand the dismissal of IEBC commissioners, after alleged bias towards the ruling Jubillee Alliance Party. (Photo by Carl De Souza/AFP Photo)