Several Christian traditions talk about the death or dormition of Virgin Mary, but all coincide to say that she was taken, body and soul, to Heaven: the Assumption. This church dates back to the 12th century, the times of the First Crusade. It is shared by the Orthodox Eastern Churches and contains the place where tradition says the body of Mary was laid before being taken to Heaven. Like in the Holy Sepulchre, what you visit here is an empty tomb.
There are two places in Jerusalem that tradition connects to this last episode of the earthly life of Mary, which is not written in the Gospels. The Dormition Abbey, close to the Upper Room, is said to be the place where she felt asleep or died. The Tomb of Mary is where the Apostles laid her body before she was assumed into Heaven.