The history of the Alaska Pipeline, which was built in the 1970s to transport oil across 800 miles of pristine wilderness, from Prudhoe Bay to Valdez. Included: the 1968 discovery of the largest oil field in North America at Prudhoe Bay; the battle between Native Americans and the government over the land the pipeline would cross; environmental concerns; and construction of the pipeline itself, which employed 78,000 people and cost more than $8 billion.