The Marble Arch is a 19th-century white marble-faced triumphal arch in London, England. The structure was designed by John Nash in 1827 as the state entrance to the cour d'honneur of Buckingham Palace; it stood near the site of what is today the three-bayed, central projection of the palace containing the well-known balcony. In 1851, on the initiative of architect and urban planner Decimus Burton, a one-time pupil of John Nash, the arch was relocated to its current site, near the northeast corner of Hyde Park, so that expansion of Buckingham Palace could proceed.