The Latin word "crypta" probably originally meant a gallery or extended room in a cavern, but it was later extended to describe man-made tunnels or tunnel like structures. By the time of Augustus, its most common usage was in descriptions of structures like the crypta Balbi: very deep pillared porches around three or four sides of a courtyard. The outside wall was usually windowless, so the ambulatory nearest the wall was dark, and hopefully cool, like a cave.
The Theater of Balbus was right between the Theater of Marcellus and the Theater of Pompey, and, although it was the smallest of the three theaters in the Campus Martius, it was the richest and most interesting architecturally. Its stage was of the finest marbles, and most intricate design. It's seating was richer, and its small size made it both more intimate and more selective in its audience. Having Balbus, one of Augustus' best Generals and most important military advisors as its patron surely would also have attracted the upper class audience.
And then there was the crypta, a place of relaxation and refreshment back stage. Roman stage productions were notoriously long, and several different plays might be run in a string -- double, triple, quadruple features and more. You went to the theater like you went to the games -- for a full day. There had to be a place to spend the intermissions, to skip a too familiar production, to gossip, to see and be seen -- to hang out. There was usually a temple in the center of the courtyard where actors prayed for good reviews and friendly audiences -- written prayers survive. Stalls for food and drink filled the space between the temple and the porticoes. There may have been canopies or roofed pavilions -- surviving pictures are hard to interpret. In higher class theater/courtyard complexes like the Theatrum and crypta Balbi, the porticoes had no commercial uses: they were richly decorated and furnished for the use of the theatergoers. (The backstage portico at Ostia had guild and shipping company offices, the one in Pompeii seems to have had travel agencies and "escort services" offices.) Balba's porticoes also had an upper level just as richly made and decorated as the courtyard level. You need to stand on the piano nobile level balcony overlooking the inner courtyard of the Palazzo Venezia gallery, three blocks to the east, to get the effect.
Over the centuries, the crypta and courtyard evolved as markets, warehouses, churches, houses, workshops, factories, hospices, food distribution centers all had their day, until it was finally abandoned to fall into ruins. Twenty years of excavation, interpretation, and restoration funded by the Jubilee Fund and Roma Capitale legislation and carried out by the Rome Archeology Board were needed to open the Museum. Work continues on adjoining structures, which will be incorporated as they are finished.
Museums come in two types: the "Wow, look at that", tourist kind and the "museo didattico" kind aimed at and frequented by serious students. The Crypta Balbi is unashamedly in the second category. Explanatory text is detailed and in English as well as Italian. Display cases and wall and floor units are simple, well lit, and not distracting. The collection is representative of the masses of artifacts found at the site and is arranged chronologically with the ground floor having the oldest and upper floors having more recent displays. Architectural elements are displayed in context and proper positions with original parts and reconstructions easily distinguishable. There are several "wells" down which you can look to see the lowest excavated levels, several meters below the ground floor.
The only complaint heard was about the modern elements -- too many dizzying sweeping and swooping stairways inside the exits and entrances. The back stairway, on the other hand is new, but very authentically "ancient Roman" in design and decoration. Except for a very small display area five meters above floor level on the top floor, the whole museum is wheel chair accessible, with elevators between floors and ramps between levels on the ground floor. Like all Roman museums the Museo Crypta Balbi needs many more chairs and benches in display areas. A small bookstore is open with a promise of a much larger one. There are clean restrooms on each level. There is no cafe or refreshment area installed or planned -- but the site is only one block from Piazza Argentina.
Internet links:
The Roma Preview announcement of
the opening -- description, location, fees, contact info:
http://www.romapreview.com/pagineing/vedere/crypta.html
Ministry of Cultural Activities
announcement (in Italian). Text is more detailed and different pictures:
http://www.beniculturali.it/ufficiostampa/comunicati/com00326.html