It is known worldwide both for being the hall in which conclaves and other official ceremonies are held, including some papal coronations, and for having been decorated by Michelangelo. It is located on the right of St. Peter's Basilica, after the Scala Regia, and originally served as the Palatine chapel inside the old Vatican fortress.

The chapel is rectangular in shape and measures 40.93 meters long by 13.41 meters wide (the dimensions of the Temple of Solomon, as given in the Old Testament). It is 20.70 meters high and is roofed by a flattened barrel vault, with little side vaults over the 6 centered windows.