The landmark ventilation buildings of State Route-99 are the transparent, brightly colored, visible manifestations of a much larger (and largely invisible) major tunnel project that lies beneath the surface of downtown Seattle. The new tunnel replaced the seismically deficient Alaskan Way Viaduct, an elevated highway that bordered the city’s western shore. The viaduct presented physical, psychological and environmental barriers to waterfront access in Seattle. Its removal allows for a more natural and organic relationship between the core of the city and the water’s edge, creating greater opportunities for increased recreational facilities, public access and economic development.