Even as the wounded are being treated and dazed tourists accompanied back to their hotels, in the wake of the Barcelona van attack a wide-ranging counter-terror operation mounted by Spanish police is already in full swing.
Officers killed five potential further attackers wearing explosive vests in a shootout in the coastal town of Cambrils. It was believed that a second van attack had been planned for the fishing port, which is 120 km south of Barcelona.
The hunt is also underway for the driver of the van which ploughed into crowds on Las Ramblas on Thursday. He is believed to have fled the scene on foot after crashing the rented vehicle to a halt.
The attack seems to have been designed to cause maximum casualties and distress. Las Ramblas is a thronging tourist street in central Barcelona, which in August is packed with people strolling along the tree-lined avenue and browsing the shops and stalls along the way.
Eyewitnesses describe their horror as the van zigzagged through the crowds, sending people flying into the air and leaving bodies strewn in its wake.
At least 13 people were killed and 100 injured in the attack, which mirrors the crude but effective method of earlier lethal attacks in Nice, Berlin, London, Stockholm, and most recently, Charlottesville.