View from a drone inside the SR 99 tunnel, executed by Bertha.
Bertha, also known as Big Bertha, is a 57-foot-diameter (17.4 m) tunnel boring machine built specifically for the Washington State Department of Transportation’s (WSDOT) Alaskan Way Viaduct replacement tunnel project in Seattle. It was made by Hitachi Zosen Sakai Works in Osaka, Japan, and the machine’s assembly was completed in Seattle in June 2013. Tunnel boring began on July 30, 2013, with the machine originally scheduled to complete the tunnel in December 2015. Wikipedia 😉