<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/640x320/54cb0ddd1bc43_-_mushroom-cloud-01-0413-de.jpg>
<http://www.popularmechanics.com/military/weapons/a8900/mushroom-cloud-physics-not-just-for-nukes-15363683/>