Under the city of Seattle, Bertha, the world’s largest tunneling machine is at work excavating what will soon become the 1.7-mile long SR99 tunnel.
At an astonishing five stories tall, and 326 foot long, Bertha represents a marvel of modern engineering. Once at full bore Bertha will be able to move 35 feet of earth a day. At that pace she’ll emerge from her subterranean home at the intersection of Sixth Avenue North and Harrison Street in around 14 months.
Watch a Video of Bertha in Action
Image and Video Courtesy of WSDOT