Podcast:99% Invisible Published On: Thu Mar 21 2013 Description: Wherever there is sufficient demand to move between two points of differing elevation, there are stairs. In some hilly neighborhoods of California–if you know where to look–you’ll find public, outdoor staircases. The large number of hidden public staircases is part … Continue reading → Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to ad-free new episodes and get exclusive access to bonus content.