Milepost 31 provides an inside look at the massive SR 99 Tunnel Project that will replace the Alaskan Way Viaduct and reconnect downtown Seattle with the waterfront. Discover the 10-foot-long interactive model of Bertha, the world's largest tunneling machine, and learn how this innovative machine operates. Located in Pioneer Square, the exhibit also highlights local history, revealing how natural and man-made forces have transformed Seattle's landscape during the past 20,000 years. Free guided tours allow visitors to get an up-close look at the project by taking them up to a viewing platform that overlooks the tunnel construction site. Self-guided tours are available as well and allow visitors to view the heart of construction along the paved pathway west of the tunnel's future south portal, near the stadiums. The guest speaker series during the First Thursday Pioneer Square Art Walk gives visitors further insight into this huge engineering project and the history of the Pioneer Square neighborhood.

Phone: (888) 298-5463

Cross Streets: Between S Main St and S Washington St