The celebrated Dutch architect and urban planner Cornelis van Eesteren is best known for his work on the General Expansion Plan for Amsterdam (Algemeen Uitbreidingsplan or AUP), dating from 1934 and implemented after the Second World War, and for his role as the chairman of the International Congress for Modern Architecture (CIAM) from 1930 to 1947. He was a pioneer and highly influential figure in what is termed modernist urbanism.