Some of the most asked questions about 9/11 as US marks 20th anniversary of tragedy

Today is the 20-year anniversary of the 9/11 terror attack that shocked the world in 2001.

The landmark anniversary has seen many documentaries – some featuring images and footage that has never been seen before – come to light.

The moment the towers fell will likely live in the memory of those who witnessed it forever, but for many Gen-Z adults today born after 2001, they weren’t even alive when the attacks took place.

As the US marks the 20th anniversary, there are some questions that get asked every year. Here’s all the answers to the most-asked questions about the tragedy.

Why is it called 9/11?

The coordinated terror attacks on New York City’s World Trade Center and The Pentagon in Washington, DC were carried out on 11 September 2001. Another plane crashed in in a field near Shanksville, Pennsylvania, and was believed to have been hijacked by terrorists.

In the United States, dates are formatted differently from the UK, with the month written first followed by the day and year.

Using the American date formulation, the events took place on 9/11/2001 – shortened to 9/11.

Some believe a unproved theory that the date was specifically selected by Osama Bin Laden and the 19 terrorists who planned and carried out the attack because 911 is the emergency services phone number in the US.

How many deaths were linked to the terror attacks?

The number of people known to have died in the 9/11 attacks is 2,977, along with the 19 hijackers.

The vast majority – 2,753 – were killed as a result of the attack on the World Trade Center, but 184 were killed at the Pentagon and 40 died when the fourth plane crashed into a field near Pennsylvania.

This toll includes all the passengers and crew – there were no survivors on the planes.

Overall, most of those who died were civilians, but hundreds of emergency service workers also died after rushing to the scenes to help.

The age of the victims ranged from two years old to 85 years old, and approximately 75 to 80 per cent of the victims were male.

Were there any survivors inside the Twin Towers?

At the time of the attack on the World Trade Center, the buildings were occupied by thousands of people – for many, it was their place of work.

Thousands managed to evacuate before the second jet hit, but just 20 people are known to have survived the collapse of the buildings. Many of those were discovered inside what remained of the north tower’s central stairwell, according to USA Today.

One man fell from the 22nd floor and miraculously landed on top of the rubble at Ground Zero.

Which tower collapsed first?

Both the north tower (1 World Trade Center) and south tower (2 World Trade Center) had 110 floors.

The north tower was struck by a hijacked plane first, followed by the south tower less than 20 minutes later.

The south tower collapsed first, around 55 minutes after being struck by the aircraft. The north tower collapsed half an hour after the south tower.

Who led the attacks?

Al-Qaeda, led by Osama bin Laden, planned the attacks from Afghanistan, where they were sheltered by the Taliban.

Nineteen people carried out the hijackings. The majority were from Saudi Arabia (as was bin Laden), while two were from the United Arab Emirates, one was from Egypt and one was from Lebanon.

What happened after?

Less than a month after the attacks, troops from the US, Britain and other countries invaded Afghanistan. Then US president George W Bush demanded the ruling Taliban handed over bin Laden, but they refused. Thus began the War on Terror, which became the longest war in US history.

Ten years later, in 2011, US troops located and killed bin Laden in neighbouring Pakistan.

The alleged planner of the 9/11 attacks, Khalid Sheikh Mohammad, was arrested in Pakistan in 2003. He is still being held in US custody at Guantanamo Bay, awaiting trial.

US troops left Afghanistan this year after nearly 20 years, with the Taliban seizing the country in a lightning quick offensive across the country.