Enos Estaus Unius escomençó la idea de mestural la conservancia natural i la coltural. Una conferencia dela Casa Branca en 1965 called for a World Heritage Trust to preserve ""the world's superb natural and scenic areas and historic sites for the present and the future of the entire world citizenry."" The International Union for Conservation of Nature developed similar proposals in 1968, and they were presented in 1972 to the United Nations conference on Human Environment in Stockholm, Sweden.