A prototype of the Space Exploration Technologies Corp. (SpaceX) Starship launch vehicle stands during an event at the SpaceX launch facility in Cameron County, Texas, U.S., on Saturday, September 28, 2019. Elon Musk gave space fans an update Saturday evening on the status of “Starship”, the next-generation vehicle his SpaceX plans to use to eventually take humans to Mars. (Photo by Callaghan O'Hare/Reuters)

A dog dressed in a costume as Greta Thunberg attends the Tompkins Square Halloween Dog Parade in Manhattan in New York City on October 20, 2019. (Photo by Johannes Eisele/AFP Photo)

A police officer reacts to flames during a protest against Chile's government in Santiago, Chile on November 4, 2019. Unrest began in Chile last October 18 with protests against a rise in transport tickets and other austerity measures and descended into vandalism, looting, and clashes between demonstrators and police. Protesters are angry about low salaries and pensions, poor public healthcare and education, and a yawning gap between rich and poor. (Photo by Henry Romero/Reuters)

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)

(L-R) Jade Chapman, Maryam Maquillage, Mariah Carey, Laura Lee and Arika Sato attend M.A.C Cosmetics Mariah Carey Beauty Icon Launch at Baccarat Hotel on December 3, 2016 in New York City. (Photo by Theo Wargo/Getty Images for M.A.C)

A young Matachin dancer sits on a the side during the annual pilgrimage in honor of Mexico's patron saint the Virgin of Guadalupe in Ciudad Juarez, Mexico, December 12, 2016. (Photo by Jose Luis Gonzalez/Reuters)

In this photo taken Friday, December 9, 2016, young ballerinas practice under the instruction of Kenyan ballet dancer Joel Kioko, 16, in a room at a school in the Kibera slum of Nairobi, Kenya. (Photo by Ben Curtis/AP 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)