Spruce Street and First Ave has an awesome "secret" swinging foootbridge, the Spruce Street Suspension Bridge, that you have to check it out! Hopefully no one is jumping on it and swingng the bridge like they were when I went on it. It's surrounded by beautiful Balboa Pak vegetation and the homey Southpark neighborhood.
Just a few more blocks down from the Spruce Street Suspension Bridge is another awesome bridge. This is not a suspension bridge, but it's beautiful and worth a stop and walk across.
Do you know of any other cool "secret" San Diego spots? Tell me!