Bostonians turned out to the city's 118th annual marathon in high spirits on Monday - one year after two deadly bombs killed three and injured hundreds by the finish line.

As thousands pounded the pavements, there were plenty of heartwarming tales along the route, including numerous marriage proposals.

One runner, falling short of the finish line, was carried over the line by competitors who were just about to complete the 26.2 mile race themselves.

Even more inspiring, however, was the appearance of several victims of last year's devastating bombing.

Helen Abbott lost part of her left leg during the explosions at the finish line, but still managed to complete the final half mile with Erin Chatham, the woman she credits with helping her get to safety as chaos ensued.

Celeste Corcoran lost both her legs below the knee during that attack, while her daughter Sydney also sustained serious injuries.

Both joined Celeste's sister Carmen Acabbo as she crossed the finish line - where they had waited fatefully for her just one year before.

Celeste Corcoran (C) and her daughter Sydney (R) finish the race with Celeste's sister Carmen Acabbo. Credit: Reuters

Two more survivors, newlyweds Patrick Downes and Jessica Kensky, rolled across the finish line on wheelchairs hand in hand. Both sustained similar leg injuries during the blasts.

Patrick Downes (L) and Jessica Kensky cross the finish line. Credit: Reuters

In spite - or perhaps because of last year's terrorist attacks - the race saw the second-largest field in its history, with 35,755 athletes registered to run and many more cheering on from the sidelines.

Buses bearing the message "Boston Strong" dropped off runners at the starting line in the town of Hopkinton. A banner on one building read: "You are Boston Strong. You Earned This."

Joel (L) and Jackie Dalton leave mementos for Martin Richard, the youngest victim of last year's bombings. Credit: Reuters

Despite all the optimism, the scars of the deadly attack remained visible on the streets of the city.

Among the signs lining the end of the route was one paying tribute to eight-year-old Martin Richard, the youngest of those killed in the bombing.

"No more hurting people. Peace," read the sign. A photograph of Martin holding a poster he made for school with those words was published after his death.