{ "items" : [
    { "id" : "http://dbpedia.org/resource/Roman_concrete"
      "properties" : {
        "http://www.w3.org/2000/01/rdf-schema#comment" : [ "Roman concrete, also called opus caementicium, was a material used in construction during the late Roman Republic through the whole history of the Roman Empire. Roman concrete was based on a hydraulic-setting cement with many material qualities similar to modern portland cement. By the middle of the 1st century, the material was used frequently as brick-faced concrete, although variations in aggregate allowed different arrangements of materials." ] ,
        "http://xmlns.com/foaf/0.1/depiction" : [ "http://commons.wikimedia.org/wiki/Special:FilePath/Rome-Pantheon-Interieur1.jpg" ] ,
        "http://dbpedia.org/ontology/thumbnail" : [ "http://commons.wikimedia.org/wiki/Special:FilePath/Rome-Pantheon-Interieur1.jpg?width=300"] } } }
