1860's Island Fortress For Sale.
Conveniently located in a highly sought-after location just 40-50 minutes from Central London, this fortress commands fabulous views of the Thames and the sea and boasts a modern red brick barracks block and concrete gun tower. Reachable by land only at low tide via a slimy brick causeway, this stronghold is an ideal location for Bond baddies and other aspiring super-villains. Distressed concrete with accents of rust throughout give it the perfect atmosphere for instilling a feeling of bleak hopeless in your guests! At £500,000, No. 1 The Thames is a real steal!
(Images from Architizer)
—Video tour at BBC site.