Nine Inch Nails and Soundgarden have become the latest rock supergroups to plan a summer tour (14). The groups will hit the road for 23 dates in July and August. The tour will begin in Las Vegas and end with a groundbreaking show at the Hollywood Bowl on 25 August (14). The members of both bands have just celebrated a key album anniversary - Nine Inch Nails' The Downward Spiral and Soundgarden's Superunknown were released on 8 March, 2004. They also shared a bill at Ontario, Canada's Molson Park the same year.