The tunnel would sit about 100 feet below the surface of a fjord. Highway E39 in Norway is one of the most beautiful drives in the world, hugging the country's rugged west coast from Kristiansand to Trondheim. It is 684 miles of unending scenery, including rivers and lakes, waterfalls and mountains and numerous fjords. But if you look carefully at a road map, E39 is something of a dotted line. Each of the breaks occurs at seven fjords -- where drivers must put their cars on a ferry to get across. This stop-and-start, sea-and-land journey takes 21 hours. But the...