I want one. Apparently these nifty things were built during the second world war to stave off invading forces coming in via the sea and to provide waterfront housing for fashionable army generals. Now it seems some are left out to rust away, others are up for sale as homes, still others have become tourist attractions.
I hadn't heard much about them to be honest and only really found these beauties by accident. So check them out for yourself and maybe even purchase what can only be described as the perfect hideout for a Bond villain. The top one is for sale for a measly 4 million pound. Ouch. I suggest a pirate life to get the booty.