(CNN) — They’re offering their spare rooms, their couches, their food, their cars — even their own beds.

A huge wave of strangers is greeting the many visitors stranded by the Boston Marathon bombings with a massive outpouring of support.

“We figure this is the least we can do,” said Heather Carey, who offered a couch at the home near Boston University she shares with roommates. “I saw a website with many others offering their spaces like we did. It is awesome to see so many people helping.”

The twin blasts Monday that left three dead and more than 140 wounded also left countless people without shelter. Investigators turned the heart of Boston into a crime scene, evacuating several hotels. This left dozens of visitors, some of them international runners unfamiliar with the area, stranded.

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By Monday evening, pleas were posted on several websites.

“Me and my friends lost our phone after the explosion,” a woman posted on Reddit. “We are visiting from Korea so our English be not very good. My friend is in the hospital now and they say we can not stay over night in hospital.”

Another woman posted: “I have no where to go.”

Quickly, the online cries for help were answered. Websites were flooded with Bostonians offering aid. Even though it was unclear how many people were helped, by early Tuesday morning a Facebook page set up for victims listed more than 100 people offering rooms and rides.

Sandeep Karnik pledged his one-bedroom condo near Fenway Park, saying someone could sleep in his bed.

“I can sleep on the couch,” said Karnik, 37. “This is unfathomable, terrible. If there is somebody in need, I can take them in.”

Karnik said he ran the marathon in 2009 for charity despite a knee injury and being slightly out of shape. He said he would have never finished the race without the support of strangers cheering him on and giving him water.

“It is my turn to give back,” he said.

Steve Trotto offered two guest rooms in his home about 45 minutes away from downtown. He said he was proud of the response from people in the New England area.

And it’s not only people in the area who were moved to action.

David Semick of Northern California was also offering support early Tuesday morning.

“Clearly I’m way out of the Boston area,” Semick said. “But maybe there is a relative that lives over here that needs something. I am here to help. I am 3,000 miles away, and I was so touched by this. So many of us want to help anyway we can.”