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 workman sweeping the highest sidewalk in the world, the 81st story of the Empire State Building, the world's tallest building, to the top of which the greatest dirigible “Los Angeles” will attempt to moor, New York, New York, early 1930s. This photo was made 1,248 feet above street level. (Photo by Adam Glickman/Underwood Archives/Getty Images)

A performer gestures at the Harbin Ice-Snow World in Harbin, northeast China's Heilongjiang Province, December 25, 2021. The 23rd Harbin Ice-Snow World opened to the public on Saturday. (Photo by Xie Jianfei/Xinhua News Agency/Profimedia via AP Photo)

Swiss grass skier Stefan Portmann in action during a free practice at the Grasski World Championships in Marbach, Switzerland, 13 August 2019. About 80 participants from 10 nations will start at the Grasski - World Championships, which will take place from 13th to 18th August 2019. (Photo by Alexandra Wey/EPA/EFE)

This undated image provided by World View shows World View capsule and balloon spacecraft that will rise to 100,000 feet above Earth for passengers to see the curvature of the planet and the blackness of space. Space tourism companies are employing designs including winged vehicles, vertical rockets with capsules and high-altitude balloons. While developers envision ultimately taking people to orbiting habitats, the moon or beyond, the immediate future involves short flights into or near the lowest reaches of space without going into orbit. (Photo by World View via AP Photo)

Supporters enjoy the atmosphere before watching England's second World Cup match against USA on the big screen at Road to Victory, Europe's largest World Cup fan park at Mayfield Depot on November 25, 2022 in Manchester, England. The English team came into their second World Cup 2022 match favoured to win. (Photo by Anthony Devlin/Getty Images)

The extravagant residence Castello di Sammezzano sits on top of a hill in Tuscany, Northern Italy. Originally it was built in the Moorish style in 1605 for Ximenes d'Aragona and then re-designed between 1853 and 1889. After the war the castello was used as a luxury hotel until closure in the mid to late 1990's. It was abandoned until April 2012 when the FPXA committee was formed, aiming to promote and enhance the castle.

Encyclopedia Britannica editions are seen at the New York Public Library on March 14, 2012 in New York City. Encyclopedia Britannica announced it will be ceasing its print edition of reference books for the first time in its 244-year history to focus solely on digital versions. (Photo by Mario Tama/Getty Images)