For many years New Zealand and other countries mined guano (bird droppings, rich in phosphate) from the Pacific island of Nauru. After the First World War, the League of Nations made Britain, Australia and New Zealand trustees over Nauru. The British Phosphate Commission was formed in 1919 with rights to phosphate mining. Nauru gained independence in 1968, but by then most of the phosphate had been stripped. Now 80% of the island is a wasteland of jagged limestone pinnacles up to 15 metres high. Australia has responsibility for rehabilitating these areas.