These tunnel boring machines are one of humanities greatest achievements. Look at their size: http://en.wikipedia.org/wiki/File:Hamburg.Trude.wmt.jpg http://en

These tunnel boring machines are one of humanities greatest achievements. Look at their size: http://en.wikipedia.org/wiki/File:Hamburg.Trude.wmt.jpg http://en.wikipedia.org/wiki/File:Hamburg.Trude.wmt.jpg It took 3 years for men and mules working 24 hours a day 6 days a week to dig a 2 mile tunnel out under Lake Michigan for Chicago's clean water in 1865. It was heralded as the 8th wonder of the world.