<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/640x480/54cb1c0fc4e1a_-_pisa-02-0913-de.jpg>
<http://www.popularmechanics.com/technology/design/a9467/laser-scanner-builds-3d-map-of-leaning-tower-of-pisa-15966081/>