The construction of the first World Trade Center complex in New York City was conceived as an urban renewal project to help revitalize Lower Manhattan spearheaded by David Rockefeller.

The World Trade Center was originally planned to be built on the east side of Lower Manhattan, but the New Jersey and New York state governments, which oversee the Port Authority, could not agree on this location.

The design and construction of the World Trade Center, most centrally its twin towers, involved many other innovative techniques, such as the slurry wall for digging the foundation, and wind tunnel experiments.

The plans, made public in late June 1960, called for a World Trade Center to be built on a 13-acre (53,000 m2) site along the East River, at the South Street Seaport, one of the Lower Manhattan ports that had seen a continuous decline in business over the past decade.

[19] Rockefeller argued that the Trade Center would provide great benefits in facilitating and increasing volume of international commerce coming through the Port of New York and New Jersey.

[27] The study also stated that Rockefeller's suggested site near the South Street Seaport was the most ideal location for the trade center, but did not take locals' possible objections into account.

[33][34] The H&M's Hudson Terminal, a large and mostly decrepit office-building complex along Manhattan's Lower West Side, was located in a neighborhood referred to as the Radio Row, which was also seeing a general decline due to a loss of transportation options.

[38] On January 22, 1962, the two states reached an agreement to allow the Port Authority to take over the railroad and to build the World Trade Center on Manhattan's lower west side.

[43] The site for the World Trade Center was the location of Radio Row, which was home to 323 commercial or industrial tenants, over one thousand offices, many small businesses, and approximately 100 residents.

[45][46] Estimates indicated that either 17,200 or 30,000 employees worked within the area that was to be occupied by the World Trade Center, and that the businesses employing them made a combined $300 million in profits every year.

[48][49][45] Newspapers published stories about small-business owners who would be affected by the evictions, while residents and tenants went around the neighborhood, carrying the effigy of a "Mr. Small Businessman" in a mock funeral.

[52] Two weeks later, a group representing approximately 325 shops and 1,000 other affected small businesses filed an injunction, challenging the Port Authority's power of eminent domain, or the takeover of private property for public use.

[56] In February 1963, the New York Court of Appeals ruled that the World Trade Center did not constitute a "public purpose", thereby nullifying the Port Authority's land acquisition.

However, after directing his staff to inspect the proposed trade center's new site at Radio Row, Tobin decided to increase the amount of floor space further, to at least 10 million square feet (930,000 m2).

[73] After it was clarified that the offer was not made in error, Yamasaki presented his "big and unmistakable, yet intimate and humane" proposal for the trade center to the Port Authority board in June 1962.

"[86] He also incorporated other features of Arabic architecture into the building design, including pointed arches, interweaving tracery of prefabricated concrete, a minaret like flight tower, and arabesque patterns.

[91] The Linnaean Society of the American Museum of Natural History also opposed the Trade Center project, citing hazards the buildings would impose on migrating birds.

[78] The framed-tube concept, earlier introduced by Bangladeshi-American structural engineer Fazlur Rahman Khan,[96] was a major innovation, allowing open floor plans and more space to rent.

[119] In designing the World Trade Center, Leslie Robertson considered the scenario of the impact of a jet airliner, the Boeing 707, which might be lost in the fog, seeking to land at JFK or at Newark airports.

[122] On April 27, 1970, the New York City Department of Air Resources ordered the World Trade Center's contractors to stop the spraying of asbestos as an insulating material.

[130] Even once the agreement between the states of New Jersey, New York, and the Port Authority had been finalized in 1962, the World Trade Center plan faced continued controversy.

[131][40] Wagner had heard of the revised West Side site through the Newark Evening News, and he stated that the Port Authority had regarded the city as an "outsider rather than the central figure" during the planning process.

[135] They claimed that the large amount of floor space in the World Trade Center would create an excess of real estate, causing a reduction in other developers' profits.

[145] As part of the agreement, the Port Authority would make annual payments to the City, in lieu of taxes, for the portion of the World Trade Center leased to private tenants.

[148] The Ajax Wrecking and Lumber Corporation was hired for the demolition work, which began on March 21, 1965, to clear the site for construction of the World Trade Center.

[150] In order to construct the World Trade Center, it was necessary to build "The Bathtub", with the slurry wall along the West Street side of the site, to keep water from the Hudson River out.

Towards the end of 1966, work began on building the slurry wall, led by Montreal-based Icanda, a subsidiary of an Italian engineering firm, Impresa Costruzioni Opere Specializzate (I.C.O.S.).

[157] Extensive use of prefabricated parts for the perimeter framing and floor truss systems helped speed up the construction process and reduce costs, while providing greater quality control.

[178] The slurry wall was in peril following the bombing and loss of the floor slabs which provided lateral support to counteract pressure from Hudson River water on the other side.

[179] The refrigeration plant on sublevel B5, which provided air conditioning to the entire World Trade Center complex, was heavily damaged and replaced with a temporary system for the summer of 1993.