The Seven Halls, or Sette Sale, is the name of the complex of cisterns located on the Oppian Hill. Previously believed to be connected to Nero's Domus Aurea, they were later found to be a large cistern supplying the Baths of Trajan. The cisterns were fed by a branch of the Trajanic Aqueduct. Found beneath the complex were the remains of a grotto lined with slabs of marble belonging to the Domus Aurea. In the fourth century CE, a domus was built on top of the complex, likely from a building used to service the tank itself. In the Middle Ages, the northernmost chambers were used as catacombs.
The complex, still quite well preserved, is built into the side of the Oppian Hill, shaped to conform to the terrain. The cisterns comprise nine (not seven) parallel chambers. The name Seven Halls comes from the fact that, when the complex was noted in the mid-18th century, only seven chambers were recognized.
References:The Château du Lude is one of the many great châteaux of the Loire Valley in France. Le Lude is the most northerly château of the Loire Valley and one of the last important historic castles in France, still inhabited by the same family for the last 260 years. The château is testimony to four centuries of French architecture, as a stronghold transformed into an elegant house during the Renaissance and the 18th century. The monument is located in the valley of Le Loir. Its gardens have evolved throughout the centuries.