Joel said documenting the Kazakh nomad summer migration was really an epic journey – a time travel journey – and at the same time was possible to get an understanding of how the balance of nature is still possible in Altai Mountains, Mongolia, June 2015. (Photo by Joel Santos/Barcroft Images)

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)

Two men push a classic Messerschmidt KR200 “Kabinenroller” at the 7th Cairo Classic Meet in Cairo, Egypt, 23 March 2019. The exhibition for classic cars is held at the Smart Village in Cairo. The exhibition is held to exchange experiences in how to preserve the old cars, and also for promoting tourism. (Photo by Mohamed Hossam/EPA/EFE)

British artist, Mark Coreth sits on top of the “Sydney Ice Bear” carved from a 10 tonne block of ice to illustrate how humans affect climate change in the Arctic at Customs House on June 3, 2011 in Sydney, Australia. The public will be welcomed to touch the bear, and leave an imprint which will begin the melting process and act as a metaphor for how humans affect the environment. The ice bear's has visited six cities on it's global tour since 2009; the visit to Sydney coincides with World Environment Day on June 5. (Photo by Lisa Maree Williams/Getty Images)

Indonesian women sit on a hill as the Suralaya coal power plant looms in the background in Cilegon, Indonesia, on January 8, 2023. A plan for how Indonesia will spend $20 billion to transition to cleaner energy was submitted Wednesday, Aug. 16, to the government and its financing partners, the planners said. (Photo by Dita Alangkara/AP Photo)