Today is a wonderful day for us all! We celebrate today Mary's "yes" to God - the day the Word became Flesh and dwelt among us!
Our salvation began on this day, the Annunciation (or Incarnation).
Side note: One of the very few days that Tolkien specifically names in The Lord of the Rings is this day, for it is this day that Frodo and Samwise were finally able to destroy the One Ring. Middle Earth's salvation began on that day.