Five times a day, a caretaker in a white knit prayer cap rolls a corrugated metal door over the side of the Al Furkan mosque in the Spanish village of Vilanova i la Geltru.
The metal muffles the muezzin’s call to prayer so that it can’t be heard across a scruffy industrial park and beyond, to beach resorts that line the glittering Mediterranean coast less than a mile away.
The green-and-white stucco warehouse-turned-mosque sits behind a padlocked 8-foot-high steel fence.
The unassuming space about 30 miles south of Barcelona is where Spanish police believe radicals planted the seed a dozen years ago for the kind of terrorist attack seen last month in Barcelona and Cambrils. The Islamic State extremist group claimed responsibility for a van attack on pedestrians in Barcelona and a knife attack in Cambrils, which together killed 16 people.