Here’s another to add. I was stationed at Cavite in Manila Bay for a number of years and was able to visit Corregidor island many times before it was cleared of vegitation and turned into a toursist trap.

Got to see the barracks, tunnels and main batteries just after they were left in WWII.

https://www.google.com/search?q=disappearing+guns+corregidor&client=safari&rls=en&biw=1221&bih=609&tbm=isch&tbo=u&source=univ&sa=X&ei=Lv9lVaawC8PfoASrxICwBg&ved=0CDAQsAQ