Just in case you don't have a chance to hear the sublime Dies Irae today, here's the Gregorian chant. There are all sorts of settings that people love, such as Mozart's or the powerful Verdi. But for my part, the plainchant is still the most beautiful, especially if sung and heard within the context of Mass.
For all the schola singers out there, I hope you survive the marathon singing of all the Propers. We're chanting the expanded Lux æterna from the Communio. Our Missa Cantata isn't until this evening, so I'm trying to rest this afternoon. I have to remind the schola that the responses are in ferial tone.