Seattle Underground (Pioneer Square)

After the Great Seattle Fire of 1889, downtown Seattle rebuilt with streets raised several feet, leaving original sidewalks and storefronts beneath the new street level. Those subterranean spaces, collectively known as the Seattle Underground, include former ground-floor businesses, sidewalks, and building basements that are no longer part of the active street grid. Portions of the Underground have been excavated and are presented on guided tours originating in Pioneer Square. The phenomenon is a direct result of the city's post-fire reconstruction and grade-raising efforts.