A bay window projects out from the exterior wall line and extends to the floor.

Many Victorian and Edwardian houses feature bay windows as a focal point for the living room at the front of the house. Houses at the coast also benefit from the extra panoramic views from the projecting window.

They were designed as an ornamental feature, but also practically, to allow more ventilation from open windows on the sides that could capture more airflow into a room.
Bay windows can flood extra light into a room and are perfect as reading spaces to benefit from the light behind.

Because of the projection from the wall, a bay window is considered an extension. A replacement bay window or built at the back of a property is allowed under permitted development, but for a new window at the front of a property, it will require planning permission.