The complex is located on an immense raised plaza erected over an earlier T-shaped base consisting of a podium, staircase, and foundation walls. These walls were built from about 24 monoliths, at their lowest level weighing approximately each. The tallest retaining wall, on the west, has a second course of monoliths containing the famous "Three Stones" (, "Trílithon"): a row of three stones, each over long, high, and broad, cut from limestone. They weigh approximately each. A fourth, still larger stone is called the Stone of the Pregnant Woman: it lies unused in a nearby quarry from the town. Its weight, often exaggerated, is estimated at . A fifth, still larger stone weighing approximately lies in the same quarry. This quarry was slightly higher than the temple complex, so no lifting was required to move the stones. Through the foundation there run three enormous passages the size of railway tunnels.