Catechism of the Catholic Church §1189 — excerpt
The liturgical celebration involves signs and symbols relating to creation (candles, water, fire), human life (washing, anointing, breaking bread) and the history of salvation (the rites of the Passover).
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.