<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/320x426/54cb0afa16e7b_-_bho-skyscraper-08-0313-de.jpg>
<http://www.popularmechanics.com/technology/design/g1122/a-brief-history-of-the-skyscraper/>