The trapezoidal building on Plaza de la Seo is the entrance to an excellent reconstruction of part of Roman Caesaraugusta's forum, now well below ground level. The remains of porticoes, shops, a great cloaca (sewer) system, and a limited collection of artefacts from the 1st century AD are on display. An interesting multilingual 15-minute audiovisual show breathes life into it all and culminates with a clever 'talking head' of a statue.