During the 1950s the governments of Canada, Denmark, and the United States built three lines of fixed radar picket sites across Canada, and with the DEW Line into Alaska and Greenland. These were the Pinetree Line (1951), the Mid-Canada Line (1956), and the Distant Early Warning (DEW) Line (1957). There was also a line of radar sites in Alaska extending westward from the end of the DEW Line to the end of the Aleutian Islands, and a line eastward from the Greenland end of the DEW Line to Iceland, the Faroe Islands, and Scotland.