How South Bridge created the vaults
Completed in 1788, South Bridge crossed the Cowgate valley on huge open arches. Once later buildings enclosed those arches and floors and ceilings were added inside them, the bridge created chambers two, three, and four storeys deep beneath the street. That is why the site feels less like a cellar and more like a buried stone district.
Who used the chambers below the street
The vaults were not built as a neat visitor curiosity. They were used for storage, workshops, and taverns, and poorer residents also sheltered in their darker corners. The history lands because you keep seeing both Edinburghs at once: the improving Georgian city above and the improvised survival below.
Why the 1860s changed their fate
By the 1860s, entrances were bricked up and the chambers slipped out of everyday use. That long abandonment helps explain the mood visitors feel now: the spaces were not polished into neatness, they survived because they were sealed away. The atmosphere is powerful partly because time never fully tidied it up.
How the vaults returned to public life
The spaces were rediscovered in the 1980s, and Mercat added Blair Street and Niddry Street vault tours to its program in 1993. That matters because the modern visit is not just about finding old rooms; it is about turning surviving Old Town fabric, archaeology, and storytelling into a coherent experience visitors can actually read.
What makes the experience feel distinctive now
The strongest part of the current format is the mix of candlelit chambers, handled artifacts, and the museum's Vaults Revealed film. It feels more immersive than a standard walk-through, but it is still anchored in real evidence from the site. That balance is why Blair Street sticks in the mind after plenty of other Edinburgh attractions fade together.