PORTALS. A portal is any gateway or doorway, insofar as it elicits ritual actions or becomes a locus of concentrated architectural symbolism. It is a space framed to call attention to spatial transition; thus it has characteristics of both a path and a place. Because a portal often separates a sacred precinct from a profane one, or a regulated from an unregulated zone, it is both a termination and a beginning. As a structure that is both inside and outside the same zone, and one that attracts dangerous as well as beneficent forces, it is a site of considerable ambivalence.

The most rudimentary forms of a portal are the cave entrance, the stone heap, the upright post, and two uprights supporting a lintel. More elaborate ones add not only familiar features such as a threshold, doors, knobs, and hinges, but also figures, inscriptions, porches, domical towers, cupolas, niches...