In a series of attacks on "precisely chosen targets," nine Islamic State militants wrought devastation in Paris on Nov. 13, 2015, killing at least 130 people.
A year later, the world is still grappling with violence exported from Iraq and Syria and carried out by those influenced by the missive to build an Islamic caliphate, even as the group's footprint shrinks.
How did Europe get to this point? And why is it so hard for authorities to stop it? This is a look back at The Post's reporting on a year of attacks, and an attempt to explain how we got there.