Gum Wall, Gum-covered brick wall in Post Alley, Pike Place Market, Seattle, United States

The Gum Wall is a brick wall in Post Alley below Pike Place Market in Seattle, entirely covered with chewing gum. The surface appears like a rainbow-colored mosaic made from thousands of sticky pieces layered on top of one another over the years.

Patrons of Unexpected Productions' Theatresports, which took over the Market Theater in 1991, began pressing used gum to the wall outside its box office, some with pennies stuck in it. The coins were removed in 1995, and around 1999 market officials reversed earlier cleanings and let the gum stay as a tourist attraction.

The wall takes its name from theater guests who started pressing chewing gum onto its surface in the early nineties. Today travelers from around the world take part in this unplanned artwork by adding their own colorful pieces, becoming part of a living tradition.

The alley sits below the main entrance of Pike Place Market and can be reached from Pike Street. The area can get narrow, especially on weekends when many people stop to photograph the wall or add their own contribution.

A cleaning operation in 2015 took over five days and removed more than a ton of chewing gum from the surface. Despite this thorough scrub, visitors immediately started adding new pieces afterward, and the wall quickly regained its colorful appearance.