Many, many people referred me to the Underground Tour in Seattle. They said it was cool to see the foundation Seattle was built upon.
They were, however, very wrong. The tour was meant to be campy, however our guide knew very little. Not only that the tour sights were pretty lame. It consists of walking around a few basements, seeing where old sidewalks were and generally spending time in dark and dank areas.
Skip this one, it's boring and pointless!