Ever wonder what the purple grids of glass are in the sidewalk? They’re vault lights dating back to the 1800s. ⁣ ⁣ In 1862 parts of Sacramento were raised as much as 14 feet to prevent flooding, so many buildings simply built over the first floor. In SF vault lights are often used to illuminate sub-sidewalk basements that lie beneath the surface.⁣ ⁣ Did you know this? Let us know in the comments below 👇 #baycurious #sacramento365 #streetsofsanfrancisco