The US fortifications might have been the best[I never knew we had all that] but they would have to be lumped in the "biggest waste of money" catagory. Germany had no stomach to cross the "channel" much less the Atlantic ocean.Japan? They just wanted our Navy out of the way. Japan[Okinawa,Iwo etc.]had the least expensive defences yet the most difficult to defeat.IMO. The Germans in Italy rank up high,too.