Part of the basement arranged through a wide corridor with workspaces for Senate staff and facilities services for equipment and material storage. Tunnel which exits the United Nations footer Boulevard has a length of 127 meters, being used to supply, drainage and technical activities, this being the central ventilation system, the thermal electricity generating units catering annexes etc. . This tunnel provides access to underground parking.

Moving through the tunnel gives visitors the opportunity to observe the resistance elements of the Palace of Parliament building, with details of how they were made of concrete reinforcement and diaphragms. Strength calculations have been made the building so that it can cope with an earthquake measuring eight on the Richter scale.