An Arctic electronic fence
Stretched across 6,900 miles (10,000 km) of Arctic tundra, the Distant Early Warning (DEW) Line was a technological marvel born of Cold War anxiety. From 1955 to 1957, a workforce of over 25,000 people built a chain of 63 radar outposts, 42 of which were in Canada. This immense undertaking, primarily funded by the United States, was designed to provide a three-to-six-hour warning of a Soviet bomber attack coming over the North Pole. Construction was a monumental logistical challenge, moving 460,000 tons of material by air, sea, and land into one of the world's most inhospitable environments, where temperatures could drop to -60°F (-51°C).
The line consisted of several types of stations. Main stations were the largest, sometimes housing up to 200 people, and were command and communication hubs. Auxiliary stations were smaller, and unstaffed "gap filler" stations used doppler radar to cover the distance between the main installations. The primary search radar at most Canadian sites was the AN/FPS-19, a high-power L-band system housed within a geodesic dome. These domes, designed to protect the sensitive rotating antennas from extreme weather, were part of this Arctic front line. The entire system became fully operational on July 31, 1957.