Construction of this imposing 140m-long building was started by the Bourbons and continued for 26 years, under three monarchs, and was the official residence of the royal family until 1931. Today, it is designated as part of the national heritage and a few of its rooms are open to the public, including the beautiful Throne Room, the sumptuous Gasparini Room, where festivities and banquets were held, and the marvellous Porcelain Room, in addition to the splendid Royal Armoury.