query: #title: Windmils in the Netherlands
  #defaultView:Map
  SELECT DISTINCT ?item ?geo ?img ?country WHERE {
    ?item (wdt:P31/(wdt:P279*)) wd:Q38720;
      wdt:P625 ?geo;
      wdt:P17 wd:Q55.
    OPTIONAL { ?item wdt:P18 ?img. }
  }