The original entrance is located on the north side, 15 royal cubits (7.9 m) east of the centerline of the pyramid. Before the removal of the casing in the middle ages, the pyramid was entered through a hole in the 19th layer of masonry, approximately 17 m above the pyramid's base level. Today tourists enter the Great Pyramid via the Robbers' Tunnel, which was long ago cut straight through the masonry of the pyramid. The entrance was forced into the 6th and 7th layer of the casing, about 7 m above the base.