Waterloo Neighborhood Park at 500 East 12th Street, Austin, Texas.

A beautiful winding creek with concrete and stone trails alongside it and lots of trees, but with homeless people camping out, and some graffiti on bridges. The part between 12th and 13th streets is the entrance to the new underground tunnel. I went there as part of a cleanup day and waded through the creek picking up occasional bits of trash - the water was nice and clear, and there was a nice breeze the whole time - the air smelled surprisingly good. Someday this park could be really nice!