Question: what is the exhibition venue in Chicago to hang out at that opened before 1977-04-14?
Answer(s):
answer: Art Institute of Chicago Building

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.01_d4)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.01_d4 ns:travel.travel_destination.tourist_attractions ?x .
?x ns:exhibitions.exhibition_venue.exhibitions_at_this_venue ?c .
?c ns:exhibitions.exhibition_run.opened_on ?num .
FILTER (?num < "1977-04-14"^^xsd:dateTime) . 
}