military defence history 19 military aircrafts 12 air defence troops 11 fortification 9 rocket weapons 8 air force 8 more ... citadels 7 radiolocation 7 construction 5 nato 5 tanks 5 military buildings 5 security policy 4 artillery weapons 4 fire arms 4 weapon systems 4 army 3 aircraft construction 3 hand firearms 3 military technology 3 military coalitions 3 reconnaissance 3 guided missiles 3 ballistic missiles 2 protection 2 fighter aircrafts 2 weapons 2 European union 1 acoustics 1 less ...