Safety measures Economic aspects 2 Navigation -- 2 Safety measures -- 2 Terrorism -- 2 Ammunition 1 Bombs 1 more ... Command and control systems -- 1 Conservation and restoration 1 Effect of terrorism on 1 Foreign relations 1 International trade -- 1 Land mines -- 1 Libraries -- 1 Library materials -- 1 Nuclear crisis control 1 Nuclear disarmament 1 Nuclear warfare 1 Nuclear warfare -- 1 Nuclear weapons -- 1 Nuclear-weapon-free zones 1 Pirates -- 1 Planning 1 Security, International 1 Shipping -- 1 Social aspects 1 Strategic aspects 1 less ...