Thanks!
I've been impressed reading accounts especially of Italy how much the sappers got up to. The Germans systematically destroyed every bridge, so each of those had to be replaced to keep the advance going. They also boobytrapped stuff all over the place, and laid mines, so that there was a constant need to clear those. And then they also got involved with 'mouseholing' in FIBUA - blasting holes in walls so that the attack could carry on without the soldiers needing to move in open streets.