On the Mount of Olives, there is a walled field surrounded by people and Olive trees. In the middle of the field is a tower that Christians erected long ago to honor the sight where the Christ was ascended and to which we expect he will sooner or later return. A stone slab in the center of the tower is the spot where the Christ’s foot last touched the earth. The Christians built the tower without a roof. Later the Muslims came and covered the tower. Whether the roof was to impede Christ’s return or to protect the stonework, I don’t know.
What I do suspect is that Christ will, as Christ usually does, find a way in, roof or not. Doesn’t seem to me he needs to return through that tower. He’s been breaking through the locked doors of our lives, anywhere and anytime, for a long while now.