Question: What attraction in San Diego, California is an amusement park that opened before June 1, 2013?
Answer(s):
answer: Belmont Park
answer: SeaWorld San Diego

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.071vr)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.071vr ns:travel.travel_destination.tourist_attractions ?x .
?x ns:amusement_parks.park.opened ?num .
FILTER (?num < "2013-06-01"^^xsd:dateTime) . 
}