There are 4 Forts in the middle of the Solent, just South of Southampton, left over from wars in years gone by. 3 of them are lived in but one hasn't been touched since the last war ended in 1945. Google Solent Forts to learn more. I have cheated and used the same fort 4 times but they are only navigational buildings you won't get your little stick man inside. On FSX you could land a helicopter on them but as there are no helicopters I don't know whether you still can. Read the .diz file for installation instructions