Now, with the Christian altar, comes a new focal point. Let us say it again: on the altar, what the Temple had in the past foreshadowed is now present in a new way. Yes, it enables us to become the contemporaries of the Sacrifice of the Logos. Thus it brings heaven into the community assembled on earth, or rather takes that community beyond itself into the communion of the saints of all times and places. We might put it this way: the altar is the place where heaven opens up.
~Benedict XVI, The Spirit of the Liturgy
Next time you’re at mass, think about that.