Did anyone else watch this on Ch5 last night? Fascinating stuff, especially the metro station for Germania and the Flak Towers around Berlin. It was clear from the sheer scale of the constructions that huge resources had been deployed to build them both in terms of raw materials and human effort - including much of the latter from slave labour The Flak Towers looked like huge mediaeval fortifications and were built in an incredible 6 months. Even the national train timetables were altered to provide enough freight capacity to deliver the necessary raw materials while they were built. Although designed primarily as anti-aircraft defences, they had a second purpose as civilian shelters and they were so impregnable that even the advancing Red Army gave up trying to take them by force and ended up going around them. Two of the three were completely destroyed by the Allies after the war, but the towers on the north face of the third still remain as the French failed to completely demolish them. Quite extraordinary.