"I couldn't tell where heaven stopped and the earth began."

"Mama always said dying was a part of life. I sure wish it wasn't." ~Forrest Gump

Part of the reason yesterday's tragic events at the Boston Marathon has hit so hard at the heart of America, is because gathering together to run or cheer at a marathon is such an iconic part of who we are. Many runners seem to have an almost spiritual connection to the pavement, and even if running isn't for you, it's hard not to be inspired by such a remarkable accomplishment. Marathons have also traditionally been so welcoming to people of all challenges, from those in wheelchairs to the blind to the very old, and their stories have continued to inspire year after year.

Several films have been made exploring why people would want to subject themselves to such a difficult race, a race so hard it has made many runners sick and rarely, worse. But runners can't stop chasing after those 26.22 miles, and some even come back year after year. Perhaps the most beautiful cinematic look at long distance running is in the 1994 film Forrest Gump, in which Forrest passes a mountain lake in Glacier National Park so clear it looks like a mirror, and watches a breathtaking sunset in the desert (You can see a brief clip of some of these dramatic running scenes above).

And here are two of our favorite documentaries:

Spirit of the Marathon. Filmmaker John Dunham follows six runners from vastly different backgrounds as they train for the Chicago Marathon, exploring the history of marathons and the appeal of such an arduous challenge. (Netflix streaming, Amazon.)

Running the Sahara. America's Charlie Engle, Canada's Ray Zahab and Taiwan's Kevin Lin embark on an unprecedented quest to traverse the entire Sahara desert -- on foot. Along the way, the runners encounter the beauties and hardships that accompany modern African life. The only weak point in this documentary is watching Charlie become less and less of a team player as the run goes on, however, it is an honest look at the imperfections of human beings as they put their bodies and minds through tremendous strain. (Netflix streaming, Amazon.)

God bless all the runners and spectators hurt, killed or witness to the terrorist attack at the Boston Marathon on Monday. Bring them peace.