the quad,

The Quad is a courtyard located on the Hogwarts Castle exterior area. It is connected to the Viaduct and the Boathouse. Four towers are located at either corner of this courtyard: The Grand Staircase Tower, Gryffindor Tower, North Tower and Stone Bridge Tower; and the Hospital Tower and Suspension Bridge Towers are located in the middle of two different sides. Gobstones players usually come into this courtyard to play "Snake Pit" and it is home to a Talking Gargoyle. The Fourth, Fifth, Sixth and Seventh floor Corridors pass right next to this courtyard.