Inside Seattle’s SR 99 Tunnel | Construction, Infrastructure & Urban Development

Explore Seattle’s SR 99 tunnel beneath downtown with Alijenga—a closer look at the infrastructure behind a modern city. The two-mile tunnel carries State Route 99 beneath downtown Seattle. Opened to drivers in February 2019, it replaced the Alaskan Way Viaduct along Seattle’s central waterfront, marking a major chapter in the city’s transportation and construction history. This journey offers a ground-level perspective on tunnel engineering and transportation infrastructure, opening a wider conversation about urban planning, waterfront redevelopment, and Seattle real estate. How cities organize roads and public spaces is an essential part of understanding their built environment. Subscribe to Alijenga for more architecture, construction, real estate, infrastructure, and city exploration from around the world.