Interesting article:

When the line blurs between sport photography and photojournalism

"I was covering the finish line at ground level at the marathon. Everything was going on as usual. It was jovial people were happy, clapping and getting to a point where it gets a little boring as a photographer. And then we heard this explosion." These words are from Boston Globe photographer John Tlumacki, who has covered more than 20 marathons in his home city. The joyous, celebratory, almost party-like finish area was suddenly transformed into a scene of devastation and destruction."