Mountain bike course in the concrete forest

Big rains all day. Did manage to have a walk taking me through the "concrete forest" a newish city park built under the I5 freeway. It's quite cool actually, and a good use of dismal space (and it is some shelter from the rain!)--the mountain bikers have a (to me) hair raising course, the dogs have an off leash area, and there are paths and steps from top to bottom and some bits of art (other than these bike posters which I think do add a certain something as well.........)