“You can hardly see the glass,” says Long Beach-based historian Stan Poe pointing at a section of sidewalk in front of the Psychic Temple. “But those were prisms that would increase the light and illuminate the basement. We don’t know what it was used for…”

At the turn of the century when electricity wasn’t common, daylight was treasured, and could be used and extended in basements via a grid of circular glass lenses in concrete reinforced by cold-twisted steel rods. A Chicago-based company’s description of the process can be read at glassian.org.

Examples of vault lights (many of which are broken and filled) can still be spotted in Downtown Los Angeles, around New York City, and a strip of Victoria, British Columbia. Poe says, “When I was a kid, I was always afraid to walk on them because they’d open!”