Remembering the World Trade Center

A terrorist attack on September 11, 2001, destroyed Manhattan's World Trade Center complex, whose twin towers were the tallest buildings in New York City and two of the tallest in the world. On that fateful day, hijacked jetliners rammed into the towers, destroying them and surrounding structures. About 2,900 people lost their lives. Called Ground Zero, the fenced-in 16-acre work site that emerged from the rubble has come to symbolize the personal and historical impact of the attack. In an attempt to grasp the reality of the destruction, to pray, or simply to witness history, visitors come to the site for a glimpse of what is left, clustering at every viewpoint along the secured area's perimeter.

The World Trade Center was much more than its most famous twins. A 16-acre, 12-million-square-ft complex, it resembled a miniature city, with a daytime population of 140,000 (including 40,000 employees and 100,000 business and leisure visitors). The center comprised seven buildings in all, arranged around a plaza modeled after, and larger than, Venice's Piazza San Marco. Underground was a giant mall with nearly a hundred stores and restaurants and a network of subway and other train stations.

Designers and critics may have debated the World Trade Center's architectural merits, but there's no disputing the ingenuity required to erect the place. Part of it had to be built below the waterline, so a giant concrete "bathtub" was built to keep the sea out. From inside the bathtub, 1.2 million cubic yards of dirt were removed. Finally, upon the foundation of Manhattan bedrock, 100 million tons of steel (a dozen different grades), glass (there are 43,000 windows), concrete (425,000 cubic tons), and other materials were built into the twin towers. Some term it one of the most ambitious engineering feats of all time.

World Trade Center Chronology

1960: Downtown/Lower Manhattan Association recommends development of World Trade Center by the Port Authority of New York & New Jersey.

1964: Architectural plan presented by Minoru Yamasaki Associates (Michigan) and Emery Roth & Sons (New York).

1966: Excavation of site begins.

1968: Steel construction begins.

1970-71: Tenants begin moving into 1 World Trade Center (north tower).

1972-73: Tenants begin moving into 2 World Trade Center (south tower).

1973: World Trade Center is dedicated.

1974: French acrobat Philippe Petit and a pal install a cable between the two towers' roofs. Petit crosses from one to the other.

1977: Mountain climber George Willig scales 1 World Trade Center.

1993: Terrorists detonate a bomb in 1 World Trade Center, creating a crater five stories deep.

1999: Thor Alex Kappfjell evades building security and sky dives from the observation deck atop 2 World Trade Center.

2001: Hijacked commercial airliners slam into towers, which collapse shortly thereafter.