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 man poses for a photo with a life size cutout of Pope Francis at Bicentennial Park where the pontiff celebrated Mass for an estimated half-million people, in Quito, Ecuador, Tuesday, July 7, 2015. Francis told an estimated half-million people gathered for the Mass that in a world divide by wars, violence and individualism, Catholics should be “builders of unity”, bringing together hopes and ideals of their people. (Photo by Ana Buitron/AP Photo)

Flowers are placed on a “comfort woman” statue during the weekly Wednesday protest in front of Japanese embassy demanding for an apology and compensation from Japanese government in Seoul, South Korea, July 22, 2015. “Comfort women” is the Japanese euphemism for women who were forced into prostitution and sexually abused at Japanese military brothels before and during World War Two. (Photo by Kim Kyung-Hoon/Reuters)

With their affinity for hunting, sneaking, and hidden blade-like retractable claw, cats are really the assassins of the animal world. They're not as intimidating when they're kittens dressed up as assassins from the upcoming Assassin's Creed Unity, but what they lack in deadliness they more than make up for in cuteness. YouTube user Mr.TVCow posted the video, in which four hooded kittens hunt down a french soldier, much like like in a number of trailers for Assassin's Creed Unity. They use their eagle vision ability, parkour after their target, and perform lethal aerial assassinations, and yes, it's as unbearably adorable as it sounds.

Wildlife photographer Kevin Fleming has covered the world as a photographer for National Geographic and has been recognized America’s Best Observer by Readers Digest. His assignments have taken him into war and famine in Somalia, to the Mediterranean for a re-creation of the voyage of Ulysses and put him on a dogsled crossing the Canadian arctic. Now Kevin is working on his 27th book. Here: Red fox kits look out from a hollow log. (Photo by Kevin Fleming)

A visitor walks inside the initiation well at Quinta da Regaleira in Sintra October 6, 2014. Sintra became the first centre of European Romantic architecture in the 19th century, which influenced the development of landscape architecture throughout Europe. It was classified as a World Heritage Site by UNESCO in 1995. Its monuments are visited by more than 1.5 million of tourists every year, according to local media. (Photo by Rafael Marchante/Reuters)

Egmont National Park in New Zealand with Mt. Taranaki at its center is seen in a Landsat 8 satellite image taken July 3, 2014 and released by NASA November 14, 2014. The image is from the book “Sanctuary: Exploring the World's Protected Areas from Space”, published by the Institute for Global Environmental Strategies with support from NASA, which was released this week. (Photo by Reuters/NASA/USGS)

Nasoin Akhter, 15, has her makeup done at a beauty parlor on the day of her wedding to a 32-year-old man, August 20, 2015, in Manikganj, Bangladesh. In June of this year, Human Rights Watch released a damning report about child marriage in Bangladesh. The country has one of the highest rates of child marriage in the world, with 29% of girls marrying before the age of 15, and 65% of girls marrying before they turn 18. (Photo by Allison Joyce/Getty Images)