<https://www.sightseeingtoursitaly.com/tips-articles/history-of-the-leaning-tower-of-pisa/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.sightseeingtoursitaly.com/tips-articles/history-of-the-leaning-tower-of-pisa/>