The eighth day. But for us a new day has dawned: the day of Christ's Resurrection. The seventh day completes the first creation. The eighth day begins the new creation. Thus, the work of creation culminates in the greater work of redemption. The first creation finds its meaning and its summit in the new creation in Christ, the splendour of which surpasses that of the first creation.
Source: Catechism of the Catholic Church (Vatican.va)