A basilica is a Christian structure designed for worship. It consists of a lengthy, rectangular shape having an apse at one end. It is divided by a row of columns and surrounded by an aisle. Windows in the upper part of the central nave provide lighting. The altar is within or before the apse that arches from the nave. Its width is never greater than one-half its length.
The shape of the basilica resulted from the ancient conversion of pagan structures into Christian use.
Basilica de Guadalupe.