CNN CNN Newsroom December 29, 2013 00:58:00
Huge underground drilling machine, has hit something and it can't get past it. stephanie elam has the story. >> reporter: no doubt, bertha is a beheem. she's the largest tunnelling machine in the world and she was put to work tunnelling in seattle for a planned highway, but bertha was oonl tenth of the way along her journey when she suddenly encountered something large enough and strong enough to stop her in her tracks. >> we're being really cautious. want to make sure we don't damage this $80 million machine. >> reporter: but what is it? g geologists point to how it was filled in by engineers...
Source: archive.org