metal

military

protection

sea

security

barbed

border

danger

fence

private

wire

barrier

defense

war

water

abandoned

freedom

iron

sharp

prison

boundary

crime

safety

background

steel

wall

zone

protect

jail

barb

forbidden

barbwire

dangerous

criminal

closeup

army

control

line

punishment

secret

symbol

restricted

concept

prisoner

base

technology

arrest

separation