Ritmeyer has pointed out that the Dome of the Rock is seated on a square platform atop the Temple Mount, the sides of which, defined by short flights of steps, are square and parallel to the modern walls of the Mount with one exception: the western steps deviate from parallel. Moreover, the bottom step on the western side of the Dome of the Rock platform is composed of a single line of distinctively large and beautifully polished ashlars. According to Ritmeyer, the measurements given in the Mishna, tractate Middot, The Temple Mount measured 500 cubits by 500 cubits, can be traced on the modern Temple Mount, with this step the outline of the western side of the square and the Eastern Wall the eastern side. The precise measurement of an ancient Judean royal cubit, 20.67 inches, outlines these landmarks area exactly. The northern edge of the ancient square was demarcated by Charles Warren, the last archaeologist permitted by the local waqf to explore the underground areas of the Mount, in his the underground structure he labeled as No. 29 in surveys he carried out in the 1860s. The southern side of the 500-cubit ancient platform square is marked by the so-called Straight Joint, a visible bend in the eastern wall. Ritmeyer proposes that this 500 cubit walled square was constructed by King Hezekiah c. 700 BCE to expand the flat area in which the faithful could gather at the Solomonic-era Temple. The Foundation Stone around which is the ancient Jewish Temple was built and which is now sheltered under the Dome of the Rock, is a natural rock outcrop at the highest point of a Mount Moriah; the natural contour of the land fell away steeply on all sides, although on the eastern side the natural contour formed a flat plateau before falling sharply to the Kidron Valley along the line where the Eastern Wall stands.