This city park, which connects to the Presidio, is like the wardrobe that leads into Narnia. You think you're just walking into a kiddie playground tucked into the dead-end 12th Avenue in the quiet, upscale Inner Richmond. But wait: This place keeps going. Walk down a staircase behind the swings, and you'll discover an entire lake (or at least an extremely large pond) separated by foliage from the cars whizzing by on Park Presidio Boulevard on their way to the Golden Gate Bridge. Keep walking around the lake, and you'll see tennis courts, and eventually a back entryway to the Presidio. Heck, by this point, you wouldn't be surprised to come upon a flute-tooting faun or the White Witch. Of course, the best part is the bragging rights of exploring an out-of-the-way park that even some locals don't know exists.