The attacks sparked the NATO-allied US invasion of Afghanistan and Iraq and began the global war on terror.

After 25 years, 100 million Americans have no memory of the day that changed everything. In an age of social media, disinformation and mistrust, that can be dangerous.

For a quarter century, the US has drone-struck weddings, abducted and tortured people at black sites and blown up fishermen, spreading terror in the name of fighting it