query: #All systems of difficulty for climbing or bouldering.
  
  SELECT ?item ?itemLabel ?subclassLabel WHERE {
    { ?item wdt:P279 wd:Q609276. }
    UNION
    { ?item wdt:P279 wd:Q5591695. }
    ?item wdt:P279 ?subclass.
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
  }