I recognized the bulding instantly (I have a small monitor; only the top half of the image was visible initially). In fact, I just shot it the other day.
I do like this -- the low angle, bright colors, high contrast, and the motion blur. All very effective.
Interesting capture. I am intrigued and keep looking at all of the things in the picture. Seems a bit over processed for basic, but I still kind of dig it.
I like the use of the blur and the very low perspective. I suspect some might ding this entry for the building being more of the scene than the runners, but I think the prominence of the building sets a strong context and local flavor for the scene. Probably a bvy entry, given the stated location and street photography style.
Really like the angle, the processing, the slow shutter. Captures the essence of the grind of a marathon - not the front runners, but those who simply push along the whole way, doing their personal best. One of my top three.
as far as challenges go, you probably could have worked with the same type shot, but have shot tighter on the runners and included less of the background.