The Alaska Highway was completed on 20 November 1942. Construction was spurred on by the bombing of Pearl Harbor and really shifted into gear when the Japanese occupied Kiska and Attu Islands in the Aleutian Chain.
Dubbed the Oil Can Highway, by the men building it, due to the enormous number of discarded 55 gallon oil drums long its route. The AlCan crossed over 200 streams and contained over 8000 culverts. 16,000 men built the 1700 mile road through the wilderness, at a cost of $138,000,000 in 8 months and 11 days.
Photos courtesy of the United States Library of Congress; Statistics come courtesy of The Thousand Mile War by Brian Garfield