Many in Barcelona feeling the strain and helplessness born of this week's attacks will tell you there is but one place in town guaranteed to help you feel a little better. Just a little less impotent.

A blood bank.

Blood banks have been overflowing in the wake of events on Thursday when an attacker, or attackers, driving a white Fiat van deliberately drove into the crowds on the city's famed pedestrian mall, Las Ramblas, killing more than a dozen people.

'My war against the terrorists'

Lika Meldrum is clearly agitated. A mother and grandmother, she can't sit still in the big, gold chair as she waits to give a second round of blood. She couldn't stop thinking aboutwhat happened in her city, she says, so she came here.

"It's a lot in my mind," she says. "And right now, what I'm doing … [giving] somebody my blood … it's like my war against the terrorists.

Barcelona blood Lika Meldrum

Lika Meldrum was one of hundreds who came to a Barcelona hospital on Friday to donate blood. (Lily Martin/CBC)

"I can't go and take the gun and, you know, fight with them. I can't. Right now, I'm fighting them [by sharing] my blood."

Meldrum came to Barcelona via Georgia (in the Caucasus) and the United States. A former nurse, she moved here with her husband two years ago to retire.

"I try to live in peace, but I don't know what's happened with this — why they're fighting, what they need. Why? What for? I just never understand that."

'We try not to be afraid today'

This particular blood clinic is located at the Sant Pau hospital. The line to give blood stretches right out the door, made up mostly of young people sitting on the ground as they wait their turn.

The duty nurse reports there had been more than 150 donations by the afternoon, and the line was still growing.

"I think that everybody can do something and help each other," said Laura Cordozo, a 33-year-old nanny from Argentina, another expat who has put down roots in the Catalan city.

Laura Cordozo Barcelona blood

Laura Cordozo and a friend await their turn to donate blood. "I think that everybody can do something and help each other," she says. (Lily Martin/CBC)

"And don't be afraid. We try not to be afraid today."

'It will just live with me forever'

There have been plenty of acts of defiance on the streets of the city. Las Ramblas was teeming with people the morning after the attack. People walked in groups big and small, hand in hand, chanting and carrying posters that read, "No to terrorism."

Ken Morris and his wife, Karen, from Liverpool, U.K., were eyewitnesses, barely escaping the path of the rampaging white van. They took shelter in one of the shops along the street, shutters pulled down, doors locked, for six hours.

"It was terror. Absolute terror," he said. "There were people running towards us. They were crying out ... The noise of the people being hit. It will just live with me forever."

The couple said they were surprised by how quickly the street had been reopened. And there are little pockets of memorials all along the boulevard.

'Solidarity for everyone'

"We never dreamt it would be like this today," Karen Morris says, adding that it made her feel proud.

"Proud of the people of the world. It's not just the Spanish. It's not just us being British. It's just every nationality coming out. It's the solidarity for everyone."

Ken and Karen Morris Barcelona

British tourists Ken and Karen Morris witnessed Thursday's deadly attack on Las Ramblas. "The van was weaving from stall to stall to try and hit every stall and cause as much damage as possible," said Ken. "The noise of people being hit. It will just live with me forever." (Lily Martin/CBC)

Nafees Hamid, a researcher who has spent three years studying extremist groups in London, Paris and Barcelona, says the city was likely chosen because of its high number of foreign residents and tourists.

"They didn't go after the Catalan population; they went after Las Ramblas, which is filled with tourists — over 34 different nationalities were present in terms of the victims of those attacks," he said.

Which leads us back to the blood bank. And the need people feel at times like these to help in some small way. A gesture that can also offer a little comfort to those doing the giving.