 A National Historic Landmark, it is an excellent example of Classical Revival architecture, and a rare surviving example of an early 19th-century public hospital building.The building is home to the Ether Dome, an operating theater which has been separately designated a National Historic Landmark as the site of the first public demonstration of the use of ether as an anesthetic.The Bulfinch Building is a rectangular structure, two stories in height, with a massive Ionic portico at the center of its longer facade.