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The 1939 World's Fair -

The idea for the World Trade Center was first born at the 1939 New York World’s Fair. A project exhibited at the fair presented the idea of world peace through trade, and one of its organizers, Winthrop W. Aldrich, was determined to bring it to life.

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Winthrop W. Aldrich -

Seven years later, Aldrich headed up a project that aimed to create a permanent trade exhibition in New York, but the idea was scrapped when a more profitable alternative arose.

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David Rockefeller -

However, Aldrich’s nephew, David Rockefeller, held on to his uncle’s idea. As a member of one of the wealthiest families in New York, Rockefeller had the power to make it happen! He decided to revitalize Manhattan, with Aldrich’s idea for the World Trade Center at its core.

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The Downtown-Lower Manhattan Association -

In 1959, Rockefeller formed an association and launched a US$250 million development plan. They decided that the World Trade Center should overtake the Empire State Building as the tallest building in the world.

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Minoru Yamasaki -

American architect Minoru Yamasaki was hired to design two buildings with 110 stories each. Yamasaki and his team of engineers came up with a revolutionary design to make it work.

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An innovative design -

Most skyscrapers in New York were constructed by stacking glass and steel boxes, but Yamasaki proposed a design of two hollow tubes supported by an outer ring of steel columns. Trusses on each floor connected these columns to the central core of the building. It was almost as if the skyscrapers had an outer skin.

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Fear and criticism -

Construction began in 1967, after great resistance and criticism from other powerful New York figures. They thought it was impossible to create such a building safely. Real estate tycoon Lawrence Wien even paid for a TV ad that claimed airplanes would crash into a building that tall.

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The 1945 plane crash -

This fear was based on the fact that a small plane had crashed into the Empire State Building in 1945 due to thick fog. Many were afraid that a similar incident would occur with the Twin Towers in poor weather conditions (a terrorist attack was never even considered). As a result of this risk, the World Trade Center was built to withstand a collision with a 707 plane, the largest plane that existed at the time.

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Finding the foundations -

To build on the chosen site in Manhattan, the engineers had to dig 70 feet (21 meters) into the ground to find bedrock. They then dropped a 22-ton (19,958 kilograms), seven-story-high steel cage into the hole and filled it with concrete to create the building’s foundation.

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The materials -

The materials used to build the towers included 200,000 pieces of steel, 3,000 miles (4,828 km) of electrical wire, 425,000 cubic yards (324,936 cubic meters) of concrete, 40,000 doors, 43,600 windows, and six acres of marble.

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The elevators -

Each tower had 97 passenger elevators, each of which could carry 10,000 pounds (4,535 kg) worth of office workers!

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The final touches -

Having begun construction in 1967, the last piece of steel was added to the north tower on December 23, 1970. Work on the towers carried on until 1973. They added more spectacular features like the five-acre outdoor plaza with the 25-foot-tall (8-meter-tall) spherical sculpture by Fritz Koenig.

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Opening day -

The World Trade Center was officially opened with a ribbon-cutting ceremony on April 4, 1973. Governor Nelson Rockefeller, David Rockefeller’s brother, made an impassioned speech: “It’s not too often that we see a dream come true. Today, we have.”

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The Sears Tower -

The World Trade Center towers were 1,360 feet (415 meters) tall. They were the tallest buildings in the world for less than a year. The Sears Tower in Chicago was completed the same year, beating the World Trade Center by less than a hundred feet (30 meters).

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Inspiration for daredevils -

Although it wasn’t the tallest building in the world for long, it was still an incredible feat of human engineering. The astonishing scale inspired various skilled acrobats and climbers to perform incredible stunts.

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Philippe Petit -

The most famous was high-wire artist Philippe Petit in 1974. He and his crew broke in and set up a tightrope between the two towers for Petit to walk across, without any safety equipment. The 2008 Oscar-winning documentary ‘Man on Wire’ tells the incredible story.

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George Willig -

Another famous stuntman was George Willig. He earned the name "The Human Fly" when he scaled the south tower with homemade climbing devices in 1977.

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A booming success -

The towers were highly profitable as office space, earning US$204 million by 1983. Smaller companies were being pushed out by rising rents and big businesses were moving in.

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The 1993 attack -

The first major tragedy that occurred at the World Trade Center was in 1993. An attack was made on the building when terrorists entered the underground parking lot with a powerful bomb in their truck. They detonated it, killing six people and wounding more than 1,000.

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Renewed security measures -

The explosion caused US$600 million in damage, but the building maintained its structural integrity. It was reopened 20 days after the attack with new security measures.

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September 2001 -

By the time September 2001 came around, the building had reached 99% occupancy of its 10.4 million square feet (966,192 square meters). On any given day, 50,000 employees would work in the towers, and a further 40,000 visitors would pass through.

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September 11 -

On September 11, at 8:45 am, an American Airlines Boeing 767 crashed into the north tower near the 80th floor. It contained 20,000 gallons of jet fuel, which contributed to the enormous fire that destroyed the floors around the crash site. It killed hundreds of people instantly, and trapped many more on the floors above.

The evacuation began and the incident appeared to be a freak accident, until the second plane hit the second tower 18 minutes later. The second tower was hit near the 60th floor, trapping even more people on the floors above.

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Two more attacks -

It became clear that a coordinated attack was taking place, as two other planes had been hijacked in addition to the two that hit the World Trade Center. One plane was crashed into the Pentagon, but the famous United Flight 93 was diverted thanks to its heroic passengers. They fought back against the hijackers and sacrificed themselves to prevent another attack. They regained control of the plane and crashed it into a rural field.

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The emergency response -

The New York emergency services responded to the attacks at the Twin Towers and helped 25,000 people escape, suffering huge losses and taking incredible risks to aid those in the burning buildings. Almost 3,000 people were killed, and 400 of them were police officers and firefighters.

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The towers collapse -

The fires raging through the towers damaged the core structure to such a degree that they both collapsed approximately one hour after being hit. This destroyed and ignited much of the rest of the World Trade Center complex below. By 10:28 am that day, one of the most impressive architectural structures in the world had been reduced to "Ground Zero."

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Long-lasting health problems -

It was the deadliest terror attack ever to take place on US soil. In addition to the initial loss of life, thousands of people living and working near Ground Zero had been exposed to toxic fumes. By 2018, 10,000 people had been diagnosed with cancer related to the September 11 attack.

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Preserving the victim fund -

Billions of dollars have been paid in support and compensation to those affected by the attacks, and in 2019 the US Senate passed a bill ensuring that the September 11 Victim Compensation Fund would be financed indefinitely.

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The September 11 memorial -

The World Trade Center Site Memorial was opened in 2011, featuring cascading waterfalls where the towers used to stand, surrounded by plaques engraved with the names of all 2,983 victims.

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The Freedom Tower -

The painful gap left in the New York skyline was eventually filled by The Freedom Tower, a 94-story building even taller than the Twin Towers. It's now known as One World Trade Center.

Sources: (History) (DoSomething)

See also: Things about 9/11 that still don't make sense

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