Chemical weapons are also cheap and highly effective. The use of chemical agents was widespread in the First World War and domestic terrorists groups have been able to manufacture and use Sarin gas in attacks. [1]  These weapons are banned despite being cheap and effective because of the unnecessary suffering they cause and because of their indiscriminate nature. Mines and gas are both ‘area denial’ weapons whose effects can linger long after the conflict in which they were employed has faded into history.  [1] Wikipedia, Sarin gas attack on the Tokyo subway,