https://en.wikipedia.org/wiki/Bertha_(tunnel_boring_machine)
"After a month's investigation, WSDOT announced that the machine's cutting blades had encountered an 8-inch-diameter (20 cm), 119-foot-long (36 m) steel pipe, one of several well casings left over from a previous 2002 drilling project..."
https://en.wikipedia.org/wiki/Bertha_(tunnel_boring_machine)#Damage_to_cutterhead_and_two-year_delay
https://en.wikipedia.org/wiki/Alaskan_Way_Viaduct_replacement_tunnel
https://www.google.ca/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=bertha+under+seattle&*
