Dear Eppp, sorry for the delay. To the point...
The galleries being shown are indeed very few, and they're about as much as I've put here. The thing is, this is underneath downtown Lisbon. Professionals are not allowed to go further in their quest, least they ruin the sewer conduits running throughout the city, besides bringing down the city in itself. Actually, it was during the sanitation works being done in 1859 that these ruins finally got to be observed and drawn up, one of the very first archaeological works undertaken in Lisbon.
Supposedly (cos one's never sure on such lack of info), these galleries were to store merchandise, coming to and from the Lisbon harbour. There had been plenty of doubts about these being the remains of a roman spa, because of one stone evocative of Aesculapius, the God of Medicine. Recent information states that this was a criptoportic: arched constructions, used frequently in unstable pieces of land to create a platform from which to build from, either temples, porticoes, or other public buildings.
No old objects were found, which further sustains the theory that this wasn't a building to be shown to the public. This can also be acknowledged by other bits of info, such as, some chambers were too low to stand tall, plus, as our historian guide told us, the Galleries were just too simple in its arches and final outlook to ever be seen by the public. Apparently not in character with the Roman rulers ;-)
Portugal, and I quite believe, the whole of Europe, northern Africa and middle East, must have ruins such as these and other traces of the Roman Empire as well, since Rome was indeed rather extensive
(map).
The building where I used to work in before, an old government building in downtown Lisbon, underwent restoration work which had to be stopped. Archaeologists had to be brought in. All sorts of objects had been found, as well as arches, a well, a double wall running vertically through the whole building (which purpouse is not know yet). Curiously enough, they've came to the conclusion that over 2000 years ago, that same building had been a prison, having kept that same function up until 30 years ago. Over 2000 years after...
That's why I'm so interested in my past and legacy, so I can understand my present better :) Hope I could be of service, if not, just holler!
It is interesting that the earthquake ended up helping people. 
