Other notable aspects of the missions were the long arcades ("corridors") which flanked all interior and many exterior walls. The arches were Roman (half-round), while the pillars were usually square and made of baked brick, rather than adobe. The overhang created by the arcade had a dual function: it provided a comfortable, shady place to sit after a hard-day's work, and (more importantly) it kept rainfall away from the adobe walls. The mainstay of any mission complex was its "capilla" (chapel). The design of chapels overall followed that of Christian churches in Europe, but tended to be comparatively long and narrow due to the size of lumber available along the California coast. Each church had a main section (the nave), a baptistry near the front entrance, a sanctuary (where the altar was located), and a sacristy at the back of the church where materials used to celebrate Mass were stored and where the priests vested. In most churches, a stairway near the main entrance led up to a choir loft.