Significant downside to relying overmuch on the National Register of Historic Places when you travel: well, first is that you're a dork. But after that is: you'll miss sites like the Fremont Troll. [Thanks, L.D., for the tip--and the hospitality.]

Beaver totem at the museum. [Confidential to S.L.: This is indisputably a beaver. Come for the buckteeth; stay for the didactic panel.]

Seattle is a cinch for my favorite American manhole cover city. I'm a fan of the ones with the city map on them. If they each had a little "You Are Here" divot annnnd didn't require people to orient themselves while standing in the middle of a downtown street--well, it would be a fine idea.