Marcie Sillman talks to Seattle Mayor Ed Murray about the Highway 99 tunnel project and the city's plan to study the safety of the viaduct.
00000181-fa79-da89-a38d-fb7f2a000000Bertha, the world's biggest tunneling machine, is a five-story-tall monstrosity of drilling tasked with digging out the tunnel for State Route 99 to replace the Alaskan Way Viaduct. It's journey to the center of the earth underneath downtown Seattle began in July 2013, and since then the project has seen its fair share of successes and failures.Follow the progress of the $3 billion megaproject with KUOW.
Seattle Mayor Murray: Bertha 'Can't Fail'

Flickr Photo/Washington State Department of Transportation CC BY-NC-ND 2.0)