For three decades, the Twin Towers were among the most recognisable structures, not only in New York but in the world. They rose above Lower Manhattan and became a symbol of the city.
This, though, also made them a target. Eight years before the September 11, 2001 attack, attackers had already tried to destroy the World Trade Center.
The Twin Towers were the two landmark 110-story skyscrapers, whereas the WTC was the entire multi-building business complex that contained them.
On February 26, 1993, a van packed with explosives was driven into the public parking garage beneath the North Tower. The bomb exploded shortly after noon. It did not bring down the towers but killed several people.
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As the first major terrorist strike on the World Trade Center, the 1993 attack was a grim prelude to 9/11. Investigators wouldn't fully uncover Osama bin Laden and Al-Qaeda’s hidden ties to the plot until 1996.
{{/usCountry}}As the first major terrorist strike on the World Trade Center, the 1993 attack was a grim prelude to 9/11. Investigators wouldn't fully uncover Osama bin Laden and Al-Qaeda’s hidden ties to the plot until 1996.
{{/usCountry}}A plan to bring down both towers
The bomb had been designed to do far more than damage the underground garage. The attackers wanted the North Tower to collapse onto the South Tower.
The blast was intended to create a chain reaction. If the North Tower fell sideways, its weight would strike the South Tower and bring both buildings down. The plan failed.
The explosion instead created a huge crater across several underground levels. It damaged the complex's power system and filled parts of the towers with smoke. The bombing happened underground, but its effects were felt throughout the buildings.
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The loss of power shut down emergency lighting. Smoke travelled through stairwells and damaged elevators. Hundreds of people became trapped in elevators. Among them were 17 kindergarten children returning from the South Tower's observation deck. They were trapped for about five hours, as per 911 memorial org.
Most of those injured were hurt during the difficult evacuation. Six people died. Five were Port Authority employees, including a pregnant woman. A businessman whose car was in the parking garage was also killed, according to the FBI archives. About 50,000 people were evacuated from the complex.
Who bombed the World Trade Center in 1993?
The bombing was organised by Ramzi Yousef and a group of associates. Yousef had entered the United States in September 1992. He eventually settled in New Jersey and began working with other extremists to build the bomb.
The device was a roughly 550-700 kg homemade explosive containing urea nitrate. It was placed inside a rented Ryder van. On the morning of February 26, Yousef and Eyad Ismoil drove the van into the World Trade Center's underground garage.
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They parked it on the B-2 level. Yousef then lit the fuse and escaped. The bomb exploded at about 12:18 pm.
The van was stolen
Later, when investigators were searching through the wreckage for clues, they found an identification number of the van from a damaged piece of the vehicle. The van had also been reported stolen.
It had been rented by Mohammed A Salameh, one of the conspirators. Salameh returned to collect his deposit on March 4, 1993 but he was arrested instead. His arrest helped investigators find other members of the group and uncover more evidence about the bombing.
The World Trade Center bombing was not an isolated plot. Investigators uncovered evidence of plans to attack other New York landmarks.
The targets included the United Nations headquarters, the Holland Tunnel, the Lincoln Tunnel and the FBI's New York office. Authorities arrested members of the group in June 1993 as they were preparing explosives.
Yousef linked to another terror plot
Ramzi Yousef was also linked to another major terrorist plot. In 1995, he was captured in Pakistan. He was later convicted in the US for his role in the World Trade Center bombing and other terrorist activity.
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Yousef wanted the destruction of both towers. Eight years later, that ambition returned in a radically different form.
The connection to 9/11
The 1993 bombing and the September 11 attacks were carried out by different groups of terrorists. The common point in the two attacks was Ramzi Yousef's uncle Khalid Sheikh Mohammed - who later became one of the principal planners of 9/11.
The 1993 bomb was powerful enough to tear through several underground levels of the World Trade Center.
On an average day in 2001, tens of thousands of people worked in the seven-building World Trade Center complex. Many more passed through it as commuters, shoppers, diners and tourists.
The September 11 attacks came from above. Two hijacked passenger planes were flown into the Twin Towers. The North Tower was struck first at 8:46 am. The South Tower was hit at 9:03 am.
The buildings that had survived the 1993 bombing eventually collapsed.
(With inputs from the 9/11 Memorial & Museum - World Trade Center history and the FBI's historical case records)