When San Diegans hear about 'hidden' or 'secret' staircases, we think 'Mt Nebo, La Mesa'... Having ridden by all the staircases that lead from La Mesa Village up to the top of Nebo Hill, a few of the staircases there are indeed well hidden (though most are prominently marked with neon green pedestrians crossing signs), though they are rather far from secret. Heck, the City of La Mesa even has a hiking map denoting all of them on their webpage and a weekly organized walk around La Mesa that passes through many of the stairs. It's happily the worst kept secret in town!
At the same time, just a couple of miles to the west the decidedly understated neighborhood of Rolando is quietly housing its own set of secret passages and staircases. I had the chance to scout them all out a while back in what turns out to be a rather cool neighborhood walking route.
Many of the entrances to the passages are quite tricky to spot. It sure doesn't help that there is no curb cut where most of them enter the street, and some of them prove to be prime curbside parking spots! Be sure to wear a sturdy pair of footwear if you decide to try this hike out, though. Most of the passages involve at least a few steps, some are fairly steep, even.