<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/480x360/54cb61b29920d_-_tree-climbing-03-0912-lgn.jpg>
<http://www.popularmechanics.com/adventure/outdoors/g1730/how-to-climb-trees-with-ropes-and-harnesses/>