The tunnel inside Bragernes Hill climbs in spiral-form from 50 m (approximately 650 feet) to over 200 m (approximately 2600 feet) above sea-level. You can literally put your steering-weel into "veer-left mode", and continue up and up until you reach he top. The tunnel, which is 1650 metres long, is formed like a coil spring, and makes six sharp turns on the ascent up to the top.
http://www.youtube.com/watch?v=sBFNfPsmck0