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.

Smart LED lighting built right into an EMT’s uniform; wearable sensors that track, record and monitor a first responder’s physiological condition; and body cameras that use cloud-based facial recognition to alert wearers to imminent threats from people in their vicinity are just some of the cutting-edge wearable technology applications being explored under the Department of Homeland Security’s EMERGE Accelerator Program for Wearable Tech for First Responders (EMERGE).

It is a rare celestial crossing that has both Hillary Clinton and Donald Trump spending election night not only in the same city, but barely more than a mile apart in midtown Manhattan -- and it is creating unprecedented security headaches for New York City.

Not since they sparred with each other on the debate stage have the Clinton and Trump orbits overlapped in this way.

Clinton is planning a big bash in a symbolically significant glass-roofed atrium that is part of the Javits convention center. Trump will be ensconced in a Hilton a mere 15 blocks away.

How would emergency management and public health officials handle a catastrophe that taxed local supplies of vaccines or medical equipment? Since 1999, the federal government has had a way to help: the Strategic National Stockpile.

The stockpile consists of warehouses that contain medicines — both those that prevent the onset of an illness and those that can treat illnesses — and medical supplies and equipment. It is not meant to be the first line of defense, but rather to supplement resources when state and local supplies run short.

Bombings in New York and New Jersey — and a stabbing attack in Minnesota the same day — underscore that homegrown attacks inspired by violent extremists are as much a threat to the United States as those directed by terrorists, the nation's Homeland Security chief says.

While all attacks are difficult to detect and prevent, Homeland Security Secretary Jeh Johnson said the United States and its allies continue to "take the fight militarily to terrorist organizations overseas" 15 years after the Sept. 11, 2001, attacks on New York and Washington.