Mery Daniel, 31, shares that spirit. “I choose to focus on the positive,” she says. “I’m happy to be alive.” Of patients like Daniel, Spaulding’s Dr. David Crandell tells PEOPLE, “It’s been incredible to see their resilience.” After a trauma like this, Daniel, who is studying for the medical boards, says, “You look at people in a different way: what’s inside of them, what defines them.” She adds, “I didn’t have a decision to make about my leg. It was gone when I woke up. To be frank, it wasn’t that emotional. I mean, it hurt. But in the grand scheme of things, I was just happy to be alive. The doctor woke me after surgery and said, ‘You’re very lucky because your heart stopped twice.’”

Professional ballroom dancer Adrianne Haslet, 32, tells PEOPLE, “The fact that people truly believe I’m going to dance again has been a big deal. I’ve had studios from all over the country send pictures with little girls holding signs that say, ‘We believe in you, Adrianne!’ That makes me believe it, especially in the hard moments.”

Heather Abbott, 38, says, “When I was in the hospital, Aviva Drescher, one of the Real Housewives of New York, came to visit. She has a prosthetic leg, and it looked just like a real leg. It had veins and a birthmark. Seeing her and speaking to her helped me feel better about what kind of choices I have. It helped me see that some things in life wouldn’t have to change that much. That was a big deal.”

The lives of the 16 people who lost limbs that day were forever changed.

Among the most grievously hurt were Marc Fucarile, 34, of Stoneham, Mass., and Roseann Sdoia, 45, of Boston, who are featured in the issue and exclusive PEOPLE videos.

Stranded when the last available ambulances raced past them, the pair were thrown in the back of a police van to be rushed to the hospital.

As the vehicle hurtled through the streets of Boston, Fucarile, whose right leg was blown off, drifted in and out of consciousness. "I thought I was going to die," says the father of a son, Gavin, 5.