<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ichef.bbci.co.uk/news/ws/560/amz/worldservice/live/assets/images/2016/03/10/160310154141_castillo_624x351_carqueroarquitectura_nocredit.jpg>
<http://www.bbc.com/mundo/noticias/2016/03/160310_castillo_matrera_espana_ecce_homo_ac>