The Scala Santa, said to be the staircase Jesus walked up in Pontius Pilate’s palace in Jerusalem, was brought to Rome by St Helena in the 4th century. Pilgrims consider it sacred and climb it on their knees, saying a prayer on each of the 28 steps. At the top, behind an iron grating, is the richly decorated Sancta Sanctorum (Holy of Holies), formerly the pope’s private chapel.
Behind the sanctuary building you’ll see a showy brick facade adorned with a gold apse mosaic. This is the Triclinium Leoninum, an 18th-century reconstruction of a wall from the original Palazzo Laterano.