Question: Give me all spacecrafts that flew to Mars.
SPARQL query:
PREFIX onto: <http://dbpedia.org/ontology/>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX res: <http://dbpedia.org/resource/>
SELECT DISTINCT ?uri
WHERE {
        ?uri rdf:type onto:Spacecraft .
        ?uri prop:planet res:Mars .
}