South Korean police officers show their martial arts' skills during the official launch ceremony of the 2012 Seoul Nuclear Security Summit on February 15, 2012 in Seoul, South Korea. The Korean National Police Agency launched a security squad, exclusively established for the successful hosting of the 2012 Seoul Nuclear Security Summit. The 2012 Seoul Nuclear Security Summit will be held in Seoul from March 26-27, 2012. (Photo by Chung Sung-Jun/Getty Images)

A combination of pictures shows people taking photos of themselves in Tiananmen Square as they celebrate National Day marking the 67th anniversary of the founding of the People's Republic of China, in Beijing October 1, 2016. (Photo by Damir Sagolj/Reuters)

Hundreds of amazonian models strutted the streets of New York in order to be given a chance to make it big in the lingerie brand as they returned for the first set of call backs. Here: Model Diane Mello attends the 2016 Victoria's Secret Fashion Show castings on October 21, 2016 in New York City. (Photo by Michael Stewart/Getty Images)

A picture shows the blood stained floor of a kindergarten following reported shelling in the rebel-held area of Harasta, on the northeastern outskirts of the capital Damascus, on November 6, 2016. At least four children were killed and 19 people injured in the government strike in Harasta, according to the Syrian Observatory for Human Rights. (Photo by Sameer Al-Doumy/AFP 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)

A sculpture is pictured at “Dismaland”, a theme park-styled art installation by British artist Banksy, at Weston-Super-Mare in southwest England, Britain, August 20, 2015. The show is Bansky's first in the UK since the Banksy v Bristol Museum show in 2009 and will be open for 5 weeks at the Topicana site. (Photo by Toby Melville/Reuters)

Models walk down the runway during the Addition Elle/Ashley Graham Lingerie Collection fashion show during the Spring 2016 Style 360 on September 15, 2016 in New York City. (Photo by Fernando Leon/Getty Images)

This photo taken November 10, 2015 shows homeless street children sleeping in a park in Manila. The Philippines has swept 20,000 homeless from the streets, cancelled hundreds of flights and declared public holidays in Manila to ensure a safe and efficient summit of 21 world leaders next week, officials say. (Photo by Jay Directo/AFP Photo)