Wtf is that holliday? lol.
The Assumption of Mary is the traditional belief held by Christians of the Catholic Church, the Eastern Orthodox Church, Oriental Orthodoxy, some Protestant churches (including Lutherans and Anglo-Catholics), that the Virgin Mary at the end of her life was physically taken up into heaven. The Roman Catholic Church teaches as dogma that Mary, "having completed the course of her earthly life, was assumed body and soul into heavenly glory."
That's what Wikipedia says, anyway.