<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/480x360/54cb27475c343_-_tunnels-12-0114-de.jpg>
<http://www.popularmechanics.com/technology/infrastructure/g1424/a-brief-history-of-tunnels/>