Curator Anna Reynolds with a doll called Pamela and a toy horse on wheels at the launch of the summer exhibition Royal Childhood at Buckingham Palace, London, which celebrates royal childhood with toys and family gifts belonging to the royal children when they were growing up, on April 2, 2014. (Photo by Sean Dempsey/PA Wire)

The National September 11 Memorial & Museum (branded as 9/11 Memorial and 9/11 Memorial Museum) is the principal memorial and museum commemorating the September 11 attacks of 2001, which killed nearly 3,000 people, and the World Trade Center bombing of 1993, which killed six. The memorial is located at the World Trade Center site, on the former location of the Twin Towers, which were destroyed during the attacks. The World Trade Center Memorial Foundation was renamed the National September 11 Memorial & Museum at the World Trade Center in 2007.

A tourist walks inside the Ice Palace glacier hollow at Hintertux glacier, located at around 3250 meters above sea level, in Zillertal, Austria, 02 March, 2016. The hollow's temperature remains constant at 0 degrees Celsius, in summer and winter alike, and is also used by the University of Innsbruck for scientific research projects. (Photo by Lisi Niesner/EPA)

In this August 31, 2017, photo, mock fish are displayed to offer to the ancestors during the “Hungry Ghost Festival” in Hong Kong. Countless hungry and restless ghosts are roaming Hong Kong, and the world, to visit their living ancestors, at least according to Chinese convention. In traditional Chinese belief, the seventh month of the lunar year is reserved for the Hungry Ghost festival, or Yu Lan, a raucous celebration marked by feasts and music. (Photo by Kin Cheung/AP Photo)

Model presents a creation from the Amir Slama collection during Sao Paulo Fashion Week in Sao Paulo, Brazil August 30, 2017. (Photo by Paulo Whitaker/Reuters)

“The power of nature”. Magma, ash and gas erupt from Mount Etna in December 2015, rising to a height of several kilometres. Winner: Nature. (Photo by Giuseppe Mario Famiani/SIPA Contest)

Saira Liaqat, 22, a victim of acid violence who was burned 4 years ago, poses in Islamabad, June 11, 2007. Saira is from Lahore and was attacked with acid thrown on her over an argument relating to an arranged marriage. (Photo by Paula Bronstein/Getty Images)

North Korean girls in similar bathing suits stand under a shower at the Songdowon International Children's Camp, Tuesday, July 29, 2014, in Wonsan, North Korea. The camp, which has been operating for nearly 30 years, was originally intended mainly to deepen relations with friendly countries in the Communist or non-aligned world. But officials say they are willing to accept youth from anywhere – even the United States. (Photo by Wong Maye-E/AP Photo)