The LA river is the antithesis of what a river could be. It's a concrete gash, looking more like a long sewer, cutting through the least picturesque parts of town, and not exactly tourist friendly. You don't see any options for a promenade, no trees lined up along the banks, and I have rarely seen it actually flowing with water (the only exceptions are when there's been a strong thunderstorm and streets are a wee risky to drive on).
It's a river that evokes gritty urban images, I'm sure it's been filmed in more than its share of movies, and I could be wrong, but it might have been the location of the car race scene in Grease. Ok, not the best example of grit, but that's the only thing that comes to mind!
The banks are littered with graffiti. The concrete slates are prime canvasses for expression. I took these photos on the train, and noticed a few weeks later on my return that some of the work has been whitewashed (city government pouring in money to eradicate petty crime). People may see graffiti as simply hooligan activity, but there is a layer of art. If I had a better shutter finger, I might have been able to take better photos, not to mention telling the train engineer to slow down!