A large portico with an eastern entrance ran all the way around the outside of the site, with a solid outer wall, a row of columns down the centre of the portico and a second row of columns around the inner side. In all there were about 260 columns placed 2 m apart, and reaching a height of at least 5 m. The portico ran around the outside of a deep, Iron-Age enclosure ditch, which separated the portico from the central space in the middle of the site. This central space contained a large Romano-Celtic temple, which stood off-centre, leading to suggestions that something else stood at the heart of the religious complex.