Question: What fun things to do in Philadelphia started reocurring before 1978?
Answer(s):
answer: Philadelphia Marathon

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.0dclg)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.0dclg ns:travel.travel_destination.tourist_attractions ?x .
?x ns:time.recurring_event.date_of_first_occurance ?num .
FILTER (?num < "1978"^^xsd:dateTime) . 
}