The love padlocks, called cadenas d’amour, multiplied until there were thousands of love tokens on the bridge, each engraved with a message of love. (Photo by Charles Platiau/Reuters)

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)

Participants take part in the Color Run near the Eiffel Tower in Paris April 19, 2015. The Color Run is a five-kilometre race, held in cities across the U.S. and also worldwide, with the aim of promoting healthy living and to benefit a charity that organizers choose in each of the cities that the run visits. Participants are doused from head to toe in different colors at each kilometre. (Photo by Benoit Tessier/Reuters)

The Toyota FCV Plus fuel cell concept car is displayed on media day at the Paris auto show, in Paris, France, September 29, 2016. (Photo by Benoit Tessier/Reuters)

A new monorail service in Houston, Texas, ready for its inaugural service. (Photo by Evans/Three Lions/Getty Images). Circa 1950

A British woman plays a piano designed especially for people who are confined to bed. Date: 1935. (Photo by Mary Evans Picture Library/Caters News)

Actress Athene Seyler attempts to contort her body, in a scene from the show, “Skin Deep”. (Photo by Sasha/Getty Images). Circa 1928