In the Old Turkic religion, the Earth is seen as square, covered by a circumscribed sky dome, the four corners of the earth lying outside the shelter of the sky. The Mongol yurt dwelling (a circular tent) with its pillar an axis mundi, or world axis, is seen as a microcosm of the universe. Some questions concerning the origin of the circle-and-square cosmology—whether, for example, the Turks and Mongols got their cosmological notions from the Indo-Iranians or from the Chinese—may be difficult to answer. One link which seems easy to identify is the influence of Indo-Iranian or Indo-European concepts on Buddhist cosmology and architecture. The plan of the Buddhist stupa was based on the square (Earth) and the circle (Heaven). The use of the circle and the square in complex ways is obvious in the ground plans of the Rawak Vihara at Khotan, in Xinjiang, of the Kanishka stupa at Peshawar, in Pakistan, and of the vast Tope-e-Rustam stupa at Balkh, in Afghanistan. The stupa at the center of the vihara (monastery) at Rawak is based on a large square platform with staircases projecting at the quarters, creating a cruciform shape. The ruins of Miran, south of Lop Nor in Xinjiang, excavated by Aurel Stein show the principal building was a massive square. On a circular base inside a round room stood a stupa not visible from the outside. Wall paintings there date from 300 A.D. And finally, the word ‘mandala’ means ‘circle.’ The mandalas central to so many forms of Buddhism are either a circle within a square or a square within a circle within a square. We will return later to the questions of historical links between similar cosmological concepts in cultures distant from each other, and will suggest that this evidence shows the religious unity of the ancient world.