Interestingly, there is a tomb (I can't recall where, right off the top of my head) which ancient tradition holds to be the tomb of Mary. It's empty.
Virtually all the earliest writings we have state Mary was assumed into heaven, body and soul. Of course, if this is true, then Mary becomes a much more important biblical personage than Protestant theology would credit. Further, both the Immaculate Conception and her Perpetual Virginity serve as underpinnings, theologically, for the dogma of the Assumption.
But it is strange, isn't it? The Mother of Our Lord, and no one seems to know where her remains are.
What's so strange about that? There are alot of NT figures we don't know where the bones are.