A van driver plowed into dozens of people enjoying a sunny afternoon on one of Barcelona’s most famous thoroughfares, killing at least 13 people and leaving 80 bloodied on the pavement. Islamic State claimed responsibility for the Barcelona assault. Pro-Islamic State accounts on the Telegram messaging service shared news of the attack. One channel, called “Expansion of the Caliphate,” posted video of the scene alongside a message in Arabic. “Terror is filling the hearts of the Crusader in the Land of Andalusia,” it said.