Underground

 When you run out of space or your building something you wish to remain hidden or better defended weres best to build but underground since the napolionic times and before building underground has been used for many different things. The oil mills in dover were built in napolionic times for storing oil in due to the low temperature in the cliffs they have also been used in both wars for different things and are now used by companys to store equipment in.

During World War 1 and 2 the best place to build bunkers and things was underground to avoid being bombed and to keep things hidden dover has a mass of underground infostructures there are many shelters and plotting rooms still remaining today. Underneath ramsgate lays europes buigest air raid shelter wich runs for over a mile. underneath dover Castle lays around 5 different levels of tunnells some from the wars and some date futher back to when the castle was built