altar, table or platform for the performance of religious sacrifice. In its simplest form the altar is a small pile, with a square or circular surface, made of stone or wood. Its features vary according to its purpose. The altar of libation usually has a drain for the liquid, and so does the altar of bloody sacrifice; the altar of burnt offering (including incense) often has a depressed hollow for a fire. Altars in Egypt, in Mesopotamia, in Greece, in Rome, and among the Aztec and the Maya were highly adorned with friezes, cornices, elaborate platforms, and canopies. At Pergamum there was a huge monumental altar 40 ft (12.2 m) high. Altars as a rule were out of doors in the ancient world and in Central America. The Christian altar is the place to celebrate the Eucharist, a sacrifice in the traditional view. In the Western Church the altar is a long, narrow table of stone or wood, often reminiscent of a tomb; at its back is a reredos, which often bears a canopy. In the Roman rite there are in the middle of the altar a crucifix and a tabernacle to contain the reserved Host, although recent legislation of Roman liturgical reform suggests that the tabernacle be placed elsewhere in the church. There is a recess in each altar containing bones of martyrs; this is even true of tiny portable altars carried by chaplains. In Eastern rites the altar is square and has no backing or reredos; it is away from the wall. Most Protestant denominations have no altar; a typical practice is to have a permanent communion table below and in front of the pulpit.