Gum wall
The Market Theater Gum Wall is a brick wall covered in used chewing gum located in an alleyway in Post Alley under Pike Place Market in Downtown Seattle. Much like Bubblegum Alley in San Luis Obispo, California, the Market Theater Gum Wall is a local landmark. Parts of the gum coating on the wall are several inches thick, and the coating is 15 feet high along a 50-foot-long section.
This has to be one of the weirdest attractions I have ever found myself wanting to see. But when you are in Seattle you cannot pass up the gum wall. For some reason back in 1993 patrons began sticking there gum on the wall after a show. The city did try to clean it up twice supposedly but eventually just gave up as it became a tourist attraction.
So if you are in Seattle at any time grab a pack of gum and head on over.