SR 99 tunneling machine - Bertha
These photos highlight the journey of Bertha, the world’s largest-diameter tunneling machine, which will dig the State Route 99 tunnel beneath downtown Seattle beginning in summer 2013. Manufactured in Japan, the five-story-tall machine arrived in Seattle in April 2013. Visit www.alaskanwayviaduct.org for more information.

Learn more about Bertha at her webpage or follow her on Twitter @BerthaDigsSR99.
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