The Sala del Casellario is dedicated to the sorting of the mail sent to MPs. Designed by Ernesto Basile as a kind of labyrinth, the room is filled with mailboxes made of glass, wood and metal, and set into the wall. Until the mid-nineties, a pneumatic tube postal delivery service was still in use. Messages were enclosed in cylindrical capsules that would be inserted into a tube and propelled by a strong blast of air through an extensive network of pipes. This old-fashioned but effective system was later replaced by computers.