Boston Marathon 2012 got underway Monday despite concerns about the impacts on runners of unseasonably-warm temperatures in the Massachusetts capital. 

Thousands of athletes from all corners of the globe took to the streets of Boston Monday morning to complete the 26.2-mile race, which is one of the most prominent marathons in the world.

Pictures from the race depict the massive crush of human bodies that any marathon features, many of whom are hoping for a shot at becoming this year's Boston Marathon champion. But others participate in the race with an end goal of simply completing the run -- which is no small feat.

Boston Marathon 2012's pack of runners includes a few celebrities, including Bachelorette star Ryan Sutter, former NFL star Tedy Bruschi and retired U.S. soccer player Kristine Lilly.

This gallery of photos will give you a good idea of what it's like to be there in Boston, watching some of the world's top distance runners battling it out to be this year's winner.

Hosted by the Boston Athletic Association, Boston Marathon 2012 is being broadcast to local residents on WBZ and nationally on Universal Sports. Live coverage is also being streamed at this link, while live video can be found here. And be sure to follow the hashtag #BostonMarathon on Twitter for live updates on what's going on in the streets of Boston during today's race.

Below is a photo gallery of all the action at Boston Marathon 2012: