2 World Trade Center (1971–2001)

The original Two World Trade Center (also known as the South Tower, Tower 2, Building Two, or 2 WTC) was one of the Twin Towers of the original World Trade Center in New York City. The Tower was completed and opened in 1973 at a height of 1,362 feet (415 m) to the roof, distinguishable from its twin, the North Tower (1 World Trade Center), by the absence of a television antenna. On the 107th floor of this building was a popular tourist attraction, "Top of the World Trade Center Observatories," and on the roof was an outdoor observation deck accessible to the public and a disused helipad at the center. The address of this building was 2 World Trade Center, with the WTC complex having its own ZIP code of 10048.

The South Tower was destroyed along with the North Tower in the September 11 attacks. At 9:03 a.m, seventeen minutes after its twin was hit, the South Tower was struck by United Airlines Flight 175. Although it was the second of the two skyscrapers to be hit by a hijacked airliner, it was the first to collapse, at 9:59 a.m., after burning for 56 minutes. Of the 2,996 people killed in the attacks, around 1,000 were in the South Tower or on the ground.

The new 2 World Trade Center, which is currently under construction, is planned to have a stairstep-shaped façade, with no observation deck, and no mechanical floors. At the National September 11 Memorial & Museum, the southern pool marks the spot where the South Tower stood.