Every Catholic church has an altar placed inside it as an essential element of the celebration of the Mass.
No matter how the specific altar was made, or how it looks, a Catholic altar has many layers of symbolism.
The Catechism of the Catholic Church offers very brief descriptions of the altar that point to its symbolic meaning:
1
The Lord’s Cross
The altar of the New Covenant is the Lord’s Cross, from which the sacraments of the Paschal mystery flow.
CCC 1182
2
Center of the Church
On the altar, which is the center of the church, the sacrifice of the Cross is made present under sacramental signs.
CCC 1182
3
table of the Lord
The altar is also the table of the Lord, to which the People of God are invited.
CCC 1182
4
Christ’s Tomb
In certain Eastern liturgies, the altar is also the symbol of the tomb (Christ truly died and is truly risen).
CCC 1182