I was visiting Seattle in July and underground tour is one of those things you should do in the city. Tickets aren't that expensive, the tour is long enough to keep you engaged, but about half of the tour is ON the ground, whereas the underground part was a little bit disappointing, but ONLY because there was not as much of old stuff to see, some of it looks like a simple basement. However the stories are quite interesting, especially told by Richard, his script is on point. I recommend it.