Query: The Principle Corridor features which type of doors?
Context: Running the length of the piano nobile of the east wing is the great gallery, modestly known as the Principal Corridor, which runs the length of the eastern side of the quadrangle. It has mirrored doors, and mirrored cross walls reflecting porcelain pagodas and other oriental furniture from Brighton. The Chinese Luncheon Room and Yellow Drawing Room are situated at each end of this gallery, with the Centre Room obviously placed in the centre.