Biggest ever? Try "The Big Dig" (in Boston) on for size.At the outset it was billed as a $2 billion job...it wound up costing something like $10 billion. And one of the tunnels they dug leaks.
Ever Barney Fag,the Congresscritter who represented that district opposed it...saying,at one point,"it would be cheaper to raise the city than to lower the highway".