allied
architecture
army
bastion
battle
british
bunker
civil
coast
coastal
combat
concrete
defence
defensive
dug out
europe
european
fortification
fortified
guard post
heritage
hexagon
hexagonal
history
invasion
landmark
military
old
pill box
pillbox
redoubt
reinforced
remains
ruin
seaboard
shelter
strength
strong
strong hold
stronghold
type 22
vintage
war
wartime
world war
world war two
wwii