Question: What structure is a tourist attraction in Houston Texas and opened before 1970?
Answer(s):
answer: Bayou Bend Collection and Gardens

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.03l2n)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.03l2n ns:travel.travel_destination.tourist_attractions ?x .
?x ns:architecture.structure.opened ?num .
FILTER (?num < "1970"^^xsd:dateTime) . 
}