The building's address was 1 World Trade Center, and the WTC complex had its own ZIP code (10048) due to its large size.

[9] Yamasaki's design for the World Trade Center, unveiled to the public on January 18, 1964, called for a square plan approximately 208 feet (63 m) in dimension on each side.

[11] Demolition work began on March 21, 1966,[12] and groundbreaking for the construction of the World Trade Center took place on August 5, 1966.

[22] The first terrorist attack on the World Trade Center occurred on February 26, 1993, at 12:17 p.m. A Ryder truck filled with 1,500 pounds (680 kg) of explosives (planted by Ramzi Yousef) detonated in the North Tower's underground garage.

[27] In February 2001, the Port Authority leased the entire World Trade Center complex to Vornado Realty Trust.

[28] However, Vornado insisted on last minute changes to the deal,[29] and the next-highest bidder, Silverstein Properties, signed a lease for the complex on July 24, 2001.

[30] At 8:46 a.m. (EDT) on September 11, 2001, five hijackers affiliated with al-Qaeda crashed American Airlines Flight 11 into the northern facade of the North Tower between the 93rd and 99th floors.

[31][32] Seventeen minutes later, at 9:03 a.m. (EDT), a second group of five terrorists crashed the hijacked United Airlines Flight 175 into the southern facade of the South Tower, striking between the 77th and 85th floors.

[34] When the North Tower collapsed, debris fell on the nearby 7 World Trade Center, damaging it and starting fires.

[41] When Flight 11 hit, all three staircases in the North Tower's impact zone were destroyed, making it impossible for anyone above the 91st floor to escape.

[43] The structures were inspired by the architectural ethic of Le Corbusier and was the seminal expression of Yamasaki's gothic modernist tendencies.

[49] The Twin Towers' facades were made of high-strength, load-bearing perimeter steel columns which acted as Vierendeel trusses.

[61] The framed-tube design using steel core and perimeter columns protected with sprayed-on fire resistant material created a relatively lightweight structure that would sway more in response to the wind.

[62] In designing the World Trade Center, Leslie Robertson considered the scenario of the impact of a jet airliner crashing into the building.

Floor unknown: Alliance Global Finance, Associated Charter Marine, Carreden Group, CIF Agency, Dimetol International Trade, Eastern Capital Corporation, Falcon International Freight, First Pacific Rim, GAC Shipping, Garwood Financial, Globe Shipping Company, GSI Cargo Service, Hachijuni Bank, Hanil Securities, Lin Brothers International, Pluto Commodities, Port Newark The 92nd floor, though technically the first floor below Flight 11's impact zone, did not have any survivors.

However, the force of the crash collapsed walls and inflicted nonstructural damage such as smashed windows,[73] broken ceiling tiles and severed electrical wires, as well as causing knee-deep flooding throughout various rooms on the 92nd floor after the water pipes burst.

[76] The situation changed very quickly when flammable aviation fuel spilled down into the 92nd floor, igniting fires that rapidly began consuming its east side; within 12 minutes of the impact, the first known fatalities from the floor occurred over a three-minute period when eight workers were forced to jump from the northern end of the tower's east side to escape a rapidly advancing wall of flames.

However, images show that the blaze on the tower’s north face eventually spread westward to their safe haven in that section of the floor, making conditions there unsurvivable.

McGinnis and a number of others had been confined to a conference room the entire time after the door jammed shut from the building buckling as the plane hit, separating them from everyone else on the floor.

Most of the floor was engulfed in flames by the time McGinnis called, with extremely limited space for the group to avoid being burned.