A bank tried to build an underground parking structure and ran into archaeological elements going back to Roman times, if not earlier. They turned it into a publicly available archaeological site. The tour is free, but set it up in advance since they can only take a few people at a time in different languages. Steps and narrow passages are worth the trouble. The Roman ruins are the most obvious, but there is more here as well. Our guide was an archaeologist, which is really helpful. It is easily worth the hour we spent.

I was looking forward to this and it didn’t disappoint. We visited at 10am and found availability on the 4pm English tour. After a mooch round the castle we returned and were guided by Maria, an archaeologist. The tour was superb and the ruins found beneath the bank are fascinating, from Phoenician and Roman ruins to more recent (18th century!) discoveries. Incredible - and free! Only drawback was, we could have spent much longer down there:)

Wow ... 2,500 years of Lisbon history in one small spot. Many tourists walk right by this museum and never know the treasures it holds. Offered by Millennium Bank at their location near the arch and main square. The bank discovered these ruins during an early 90s renovation project and decided to preserve them and make it publicly available. Can only be visited via a free, guided tour. An interesting and well-documented brochure also is provided with the visit.