View of Lower Manhattan from the Manhattan Bridge, September 11, 2001

On September 11, 2001, two of the planes were flown into the towers of the World Trade Center in New York City, a third plane hit the Pentagon just outside Washington, D.C., and the fourth plane crashed in a field in Pennsylvania. Often referred to as 9/11, the attacks resulted in extensive death and destruction, triggering major U.S. initiatives to combat terrorism and defining the presidency of George W. Bush. Over 3,000 people were killed during the attacks in New York City and Washington, D.C., including more than 400 police officers and firefighters

Minoru Yamasaki's design for the World Trade Center unveiled to the public on January 18, 1964. Minoru Yamasaki (山崎 實 Yamasaki Minoru, 1 December 1912 – 6 February 1986) was an American architect, best known for designing the original World Trade Center in New York City. The World Trade Center was one of the most striking American implementations of the architectural ethic of Le Corbusier and was the seminal expression of Yamasaki's gothic modernist tendencies. He was also inspired by Arabic architecture, elements of which he incorporated in the building's design. The buildings were designed with narrow office windows 18 inches (46 cm) wide, which reflected Yamasaki's fear of heights as well as his desire to make building occupants feel secure. His design included building facades sheathed in aluminum-alloy. At the time of their completion, the Twin Towers — the original 1 World Trade Center, at 1,368 feet (417 m); and 2 World Trade Center, at 1,362 feet (415.1 m)—were the tallest buildings in the world. During its existence, the World Trade Center experienced several major incidents, including a fire on February 13, 1975, a bombing on February 26, 1993. On the morning of September 11, 2001, two Boeing 767 jets flew into the North and South Towers within minutes of each other; two hours later, both towers collapsed.