The shape of a cross
Basilica, in the Roman Catholic and Greek Orthodox churches, a canonical title of honour given to church buildings that are distinguished either by their antiquity or by their role as international centres of worship because of their association with a major saint, an important historical event, or, in the Orthodox Church, a national patriarch. The title gives the church certain privileges, principally the right to reserve its high altar for the pope, a cardinal, or a patriarch, and special penitential privileges that remove the basilica from local geographical jurisdiction and give it international status.