Mary King was one of 400 people killed by the Black Death in 1645, after the street where they lived was blocked off.
The poor plague victims were given supplies of coal, bread and beer, and left to die to stop the disease spreading.
Spooky staircase
By the 1750s, much of the street - now known as Mary King's Close - was buried underground when the City Chambers were built on top.
On Wednesday, workmen dug a hole in the floor of the council building to reveal to the public a spooky staircase leading down to Mary King's Close.
It'll soon be opened fully to tourists, so the bravest of you can climb down and investigate the narrow lanes for yourselves.
But be warned - the people running the new attraction say it will contain "a lot of gruesomeness!"
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