The original World Trade Center (WTC) was a large complex of seven buildings in the Financial District of Lower Manhattan in New York City. It opened on April 4, 1973, and was destroyed during the September 11 attacks in 2001. At the time of their completion, the Twin Towers, including the original 1 World Trade Center (the North Tower) at 1,368 feet (417 m), and 2 World Trade Center (the South Tower) at 1,362 feet (415.1 m), were the tallest buildings in the world. Other buildings in the complex included the Marriott World Trade Center (3 WTC), 4 WTC, 5 WTC, 6 WTC, and 7 WTC. The complex contained 13,400,000 square feet (1,240,000 m²) of office space and, prior to its completion, was projected to accommodate an estimated 130,000 people.

The core complex was built between 1966 and 1975, at a cost of ~$400 million (equivalent to ~$3.80 billion in 2023). The idea was suggested by David Rockefeller to help stimulate urban renewal in Lower Manhattan, and his brother Nelson, then New York's 49th governor, signed the legislation to build it. The buildings at the complex were designed by Minoru Yamasaki. In 1998, the Port Authority of New York and New Jersey decided to privatize it by leasing the buildings to a private company to manage. It awarded the lease to Silverstein Properties in July 2001. During its existence, the World Trade Center symbolized globalization and the economic prosperity of the U.S. Although its design was initially criticized by New Yorkers and professional critics—"they put up the boxes instead of the buildings"—the Twin Towers became an icon of New York City.