<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/320x426/54cb27448693c_-_tunnels-05-0114-de.jpg>
<http://www.popularmechanics.com/technology/infrastructure/g1424/a-brief-history-of-tunnels/>