During my school days, there were single dates which merited special chapters. The day when Archduke Ferdinand was shot. The day when Hitler took power. The day when Pearl Harbour was attacked.

These dates were important not just for what happened on those days. They were important for the events they unleashed in the days, weeks and years after. Days which proved the tipping point for tens of countries and millions of people.

Today's schools have a new date. September 11, 2001.

During my school days, there were single dates which merited special chapters. The day when Archduke Ferdinand was shot. The day when Hitler took power. The day when Pearl Harbour was attacked.

These dates were important not just for what happened on those days. They were important for the events they unleashed in the days, weeks and years after. Days which proved the tipping point for tens of countries and millions of people.

Today's schools have a new date. September 11, 2001.

This year marks the tenth anniversary of that most spectacular of terrorist attacks. Time enough to look back and reflect.

Time enough to answer questions like: how well did security organisations react? What were the successes and failures? And what would we do differently today?

In this edition of NATO Review, we look at the effect on NATO in the 10 years that have followed. And we include the then NATO's Secretary General's account of how he spent that historic day.

A recent edition of a security magazine highlighted what it felt were 10 events in the past 10 years which were more important to security than the events of that day. It included events like the economic crisis and the Arab Spring.

The magazine may be right. But there are no rivals to that date as the most iconic for 21st century security. It is the date which will forever have its own chapter.

Paul King