Many can remember exactly where they were 20 years ago when al-Qaida perpetrated the single deadliest terrorist attack in human history by deliberately crashing passenger planes into the twin towers of the World Trade Center in Manhattan.
Fewer, however, really contemplate just how much the 9/11 atrocity profoundly changed and shaped everyday life today.
Now, the Imperial War Museum (IWM) in London is to mark the 20th anniversary of the four coordinated attacks on 11 September 2001, which claimed almost 3,000 lives, with a series of events bringing this pivotal moment in history to the foreground in an attempt to fully understand the consequences.
It will be the first time the museum has examined 9/11 in detail, and Louise Skidmore, its head of contemporary conflict, said: â€œAnd the reason we are choosing to mark the 9/11 anniversary is because it is an event that really did have a global impact. Beyond just the geopolitical, it went into numerous aspects of our social, economic and cultural lives.
â€œEveryone remembers where they were. It was such a seismic event. But thousands and thousands of our audience were not alive and will not remember 9/11. And so they may, to a degree, look back and say: â€˜What does it really have to do with my life? Was it a big deal?â€™ It was a huge deal.â€
Through a series of events, the museum aims to examine the radical way it has changed lives across the globe.
The military aspects were the most immediate, from the historic invocation of Natoâ€™s collective defence article 5 â€“ an attack on one is an attack on all â€“ for the first time, to the invasion of Afghanistan, the global war on terror, and setting the conditions for the US-led invasion of Iraq in 2003.
â€œIt radically changed both foreign and defence policies across the globe,â€ said Skidmore.
â€œBut also so much on the home front, like anti-terror legislation, increases in surveillance, changes in attitudes towards civil liberties, air travel. All those things are as a result of the events of 9/11, to a degree.
â€œAlso, there is the fundamental impact it had on shifting attitudes towards immigration, a rise in anti-Muslim discrimination.
â€œAnd, with the focus on defence and security, there is not the focus on other things, perhaps, whether that is climate change, economic inequality, structural racism. All those things we have seen come up in the last year, a lot of those were pushed to the side because we were so focused on defence and security after 9/11.â€
The anniversary programme will showcase some of IWMâ€™s collection, including girders from the twin towers, artwork reflecting the war on terror, and a union flag rescued from Ground Zero, the site of the attack, and given to the UK.
Through a series of physical and online events, and in collaboration with other organisations across the world, the museum plans to promote dialogue and drill down into personal accounts from individuals affected, including those involved in subsequent military operations against Isis.
â€œWe are really hoping to be able to make it as global as possible, and participatory through the idea of where were you, and how has it shaped your life, starting with the personal and how the personal becomes global. That really is the best way of showing this really has a global impact.â€
The programme of events, still in the planning stage, will launch around the time of the 20th anniversary.
â€œI think a lot of people donâ€™t fully understand the repercussions 9/11 had,â€ Skidmore said. â€œItâ€™s important to understand how we have come to where we now are.â€
The four coordinated attacks by al-Qaida against the US resulted in almost 3,000 fatalities and more than 25,000 injuries and long-term health consequences.
American Airlines Flight 11 and United Airlines Flight 175 crashed into the two towers of the World Trade Center, causing them to collapse, while American Airlines Flight 77 crashed into the Pentagon and United Airlines Flight 93 crashed into a field in Pennsylvania after passengers took on the hijackers.