If you've got shopping in mind, you'll find that Downtown Houston features The Shops at Houston Center and a branch of Foley's department store. However, it also hides a wealth of businesses in tunnels beneath the city streets. Initially constructed in 1935 to link three theaters, the tunnels have been expanded to encompass more than six miles of territory and link approximately 82 buildings. The air-conditioned complex now offers dozens of shops and restaurants. Tours of the tunnels are available (713-222-9255).