AAA Editor Notes
Milepost 31 is at 211 First Ave. S. (between S. Washington and S. Main sts.). Named for the point where SR 99 enters Pioneer Square, this information center showcases the people and projects that have transformed the historic district from prehistoric times to the present.
A major focus is the Washington State Department of Transportation's SR 99 Tunnel Project, which will replace the Alaskan Way Viaduct along the downtown waterfront with the nation's largest (in terms of diameter) bored tunnel.
Four display areas—You Are Here, Moving Land, Moving People and Moving Forward—examine how natural and man-made forces have transformed the Seattle area's landscape over thousands of years and educate visitors about tunnel technology. On display are interactive exhibits, artifacts, 3-D models and pieces of tunneling equipment. One-hour walking tours to a viewing platform overlooking the tunnel construction site are offered.
Note: Closed-toed shoes are required for walking tours.
Guided tours are available.