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)

A David Cameron look-alike poses with a polar bear model outside the Houses of Parliament as part of a Greenpeace protest on May 13, 2011 in London, England. The environmental charity Greenpeace arranged the protest to highlight the first anniversary of David Cameron’s speech when he pledged to make his new government the greenest ever. In April 2006 Mr Cameron traveled by huskie-drawn sledge when he visited the island of Svalbard in Norway to witness the effects of climate change. (Photo by Oli Scarff/Getty Images)

Piper Hoppe, 10, from Minnetonka, Minnesota, holds a sign at the doorway of River Bluff Dental clinic in protest against the killing of a famous lion in Zimbabwe, in Bloomington, Minnesota July 29, 2015. A Zimbabwean court on Wednesday charged a professional local hunter Theo Bronkhorst with failing to prevent an American from unlawfully killing “Cecil”, the southern African country's best-known lion. The American, Walter James Palmer, a Minnesota dentist who paid $50,000 to kill the lion, has left Zimbabwe. He says he did kill the animal but believed the hunt was legal and that the necessary permits had been issued. (Photo by Eric Miller/Reuters)

A light-up bow whose arrows are advertised as flying up to 145 feet and the “Catapencil” – a pencil with a miniature slingshot-style launcher on its end – are on an annual list of unsafe toys released Wednesday by a Massachusetts-based consumer watchdog group. World Against Toys Causing Harm, or W.A.T.C.H., issued the “10 Worst Toys” list to remind parents and consumers of the potential hazards in some toys as the holiday shopping season gets underway. (Photo by Charles Krupa/AP Photo)

Ultra-Orthodox Jews dance next to a bonfire during celebrations for the Jewish holiday of Lag Ba-Omer in Jerusalem's Mea Shearim neighbourhood May 25, 2016. This day marks the hillula (celebration, interpreted by some as anniversary of death) of Rabbi Shimon bar Yochai, a Mishnaic sage and leading disciple of Rabbi Akiva in the 2nd century, and the day on which he revealed the deepest secrets of kabbalah in the form of the Zohar (Book of Splendor), a landmark text of Jewish mysticism. (Photo by Ronen Zvulun/Reuters)

Russian servicemen drive a partially covered T-14 Armata tank along a street before a rehearsal for the Victory Day parade in Moscow, Russia, April 29, 2015. Russia will celebrate the 70th anniversary of the victory over Nazi Germany in World War Two on May 9. (Photo by Maxim Zmeyev/Reuters)

A logometer used to determine the Titanic's speed is seen among artifacts recovered from the RMS Titanic wreck site at a press preview of a Titanic artifact auction at the Intrepid Sea, Air & Space Museum on January 5, 2012 in New York City. On April 11, 2012, the 100th anniversary of the maiden voyage of the Titanic, Guernsey's will auction the complete collection of more than 5,000 artifacts recovered from the Titanic wreck site. (Photo by Mario Tama/Getty Images)

A model presents a creation by British designer Christian Cowan at New York Fashion Week Spring 2019 in New York, New York, USA, 08 September 2018. The Spring 2019 collections are presented from 06 to 14 September. (Photo by Alba Vigaray/EPA/EFE)