ANTI INVASION DEFENCE SITE

SN Sites, buildings and structures associated with the prevention of an invasion by a hostile force.
CL DEFENCE
NT ANTI LANDING OBSTACLE
ANTI SEAPLANE OBSTACLE
ANTI SUBMARINE DEFENCE
ANTI TANK ISLAND
ANTI TANK OBSTACLE
AUXILIARY UNIT SITE
CENTRE OF RESISTANCE
DEFENCE LINE
DEFENDED LOCALITY
DEMOLITION CHARGE SITE
NODAL POINT
PETROLEUM WARFARE SITE
RAILBLOCK
RIVER DEFENCE SITE
STOP LINE
VULNERABLE DEFILE