Kenya Nadry, a website designer, took her 5-year-old nephew to a playground.
"There's still some sense of fear, but I feel like Boston's resilient," she said. "The fine men in blue will take care of a lot of it."
Police were stationed on street corners across downtown Boston, while National Guardsmen set up tents on the Boston Common and stationed tactical vehicles.
Dr. Horacio Hojman, associate chief of trauma at Tufts Medical Center, said patients were in surprisingly good spirits when they were brought in.
"Despite what they witnessed, despite what they suffered, despite many of them having life-threatening injuries, their spirits were not broken," he said. "And I think that should probably be the message for all of us — that this horrible act of terror will not bring us down."
President Barack Obama and his challenger in the last election, former Massachusetts Gov. Mitt Romney, planned to visit Boston on Thursday to attend a service honoring the victims.
The blasts killed 8-year-old Martin Richard, of Boston, and 29-year-old Krystle Campbell, of Medford. The Shenyang Evening News, a state-run Chinese newspaper, identified the third victim as Lu Lingzi, a graduate student at Boston University.