Downtown Seattle is were you'll find the now famous The Market Theater Gum Wall, famous as in, its been given its ownWikipedia page. Established 1993, visitors of the Unexpected Productions' Seattle Theatresports have been sticking gum to the wall and placing coins in "gum blobs" for good luck.
Call it a habit that has become a trend took off, and now some parts of the 50 foot long wall are several inches thick with used gum. At two points in time theatre workers have tried to scrape the gum away, but eventually gave up when market officials deemed the gum wall a tourist attraction. As well as being named the second germiest tourist attraction, scenes for famous films such as Love Happens starring Jennifer Aniston have been shot with the wall as a backdrop.