(Italian: Holy Stairs)
Twenty-eight white marble steps at Rome, near the Lateran.
According to tradition, it is the staircase that formerly led to teh praetorium of Pilate at jerusalem, and hence was sanctified by the footsteps of Our Lord during His Passion.
They are supposed to have been brought from Jerusalem to Rome by Saint Helena, c.326.
In the Middle Ages they were known as Scala Pilati, the Stairs of Pilate.
When the old papal palace was destroyed in 1589, and the new one built, the Holy Stairs were transferred to their present site before the Sancta Sanctorum.
Here they are flanked by four other stairs, two on each side, for comon use, since the Holy Stairs may only be ascended on the knees, a devotio popular among pilgrims and the Roman faithful.
Pope Pius X granted a plenary indulgence to be gained as often as the stairs are devoutly ascended, after confessoin and communion.
Imitations of the Scala Santa have been built elsewhere and indulgences are attached to them.
New Catholic Dictionary