2. The terrorist attacks that killed at least 14 people in Spain appear to be a sophisticated and far-reaching plot that could have been much worse.

The Spanish police said the attacks, the first in Barcelona and a second episode in which five men in a car hit people in the seaside resort town of Cambrils, may have been hatched in a house that the plotters were using as a bomb factory. At least four suspects were arrested, and the Islamic State claimed responsibility for the Barcelona assault.

Here’s what we know about the attacks, and our Interpreter column examines the effects on society if anything — even something as ubiquitous as a car — can be used as a weapon.