Major American Municipal Proojects

Bertha, one of the world's largest boring machines, will cut through a thick concrete wall at midday on Tuesday if all goes according to plan, completing the most difficult phase of building a highway under the heart of downtown Seattle.

Bertha, one of the world's largest boring machines, will cut through a thick concrete wall at midday on Tuesday if all goes according to plan, completing the most difficult phase of building a highway under the heart of downtown Seattle.