The Western Wall's holiness in Judaism is a result of its proximity to the Temple Mount. Because of the Temple Mount entry restrictions, the Wall is the holiest place where Jews are permitted to pray, though the Foundation Stone, the most sacred site in the Jewish faith, lies behind it. The original, natural, and irregular-shaped Temple Mount was gradually extended to allow for an ever-larger Temple compound to be built at its top. This process was finalized by Herod, who enclosed the Mount with an almost rectangular set of retaining walls, made to support the Temple platform and using extensive substructures and earth fills to give the natural hill a geometrically regular shape. On top of this box-like structure, Herod built a vast paved platform that surrounded the Temple. Of the four retaining walls, the western one is considered closest to the former Holy of Holies, which makes it the most sacred site recognized by Judaism outside the previous Temple Mount platform.