Single Form was Babara Hepworth's largest work at 21 feet in height (6.4 metres) and cast in bronze. It was her most significant public commission. It stands in the United Nations Plaza in New York. Single Form was commissioned by the Jacob and Hilda Blaustein Foundation as a memorial to Hammarskjöld after his tragic death in an air crash in 1961. (Single Form, 1961-4, United Nations Building, New York)