Wilson’s Arch. The vaulted area below the arch is entered from the open-air prayer plaza in front of the exposed portion of the western wall and serves as a supplemental space for prayer services when the plaza is crowded with holiday worshipers or during bad weather. Wilson’s Arch was long thought to have supported a bridge connecting the Temple Mount with the western portion of Jerusalem. We now know that it also supported a viaduct and an aqueduct bringing water from springs southwest of Bethlehem to the Temple.