The Bulfinch Pavilion of the Massachusetts General Hospital is located on the hospital’s main campus on Fruit Street in the West End. It was designed by architect Charles Bulfinch, and built between 1818 and 1823. While the building was designed by Bulfinch, he had relocated to Washington to assume the duties of the architect of the U.S. Capitol in 1817 and Alexander Parris became responsible for its execution. A major expansion of the wings and a self-supporting staircase occurred in 1844-46 and was overseen by George Perkins. A National Historic Landmark, it is a rare surviving example of an early nineteenth century public hospital building. The building is home to the Ether Dome, an operating theater with semi-circular banked seats for observers. Here in 1846, Dr. John C. Warren, one of the hospital founders, performed the first operation using ether as an anesthetic.