From A Wiki of Ice and Fire
Castle Stair is a street in White Harbor.
The broad street is pebbled with white stones and has steps that lead up from the Wolf's Den by the harbors to the New Castle on top of the city's hill. Marble mermaids light the way, bowls of burning whale oil cradled in their arms. From the top there is a view down to both the inner and outer harbor. There is a long tunnel that secretly runs below the Castle Stair connecting the Wolf's Den and the New Castle.
A Dance with Dragons
Ser Davos Seaworth walks the Castle Stair on his way to New Castle, and later on he is escorted by Robett Glover on the secret passage underneath it.
- ↑ 1.0 1.1 1.2 A Dance with Dragons, Chapter 29, Davos IV.
- ↑ 2.0 2.1 A Dance with Dragons, Chapter 15, Davos II.