The term 'Altar Section of a Church' can be summarized by the word 'APSE, ' which is a four-letter word. An APSE is a semicircular recess in the wall of a church, usually at the east end, containing the altar. It is often decorated with mosaics or frescoes and is sometimes flanked by two towers. The APSE is a common feature of early Christian and Byzantine churches, and is also found in some Islamic mosques.