Question: What zoo that opened on May 1, 1838 in Amsterdam can people go to?
Answer(s):
answer: Natura Artis Magistra

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.0k3p)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.0k3p ns:travel.travel_destination.tourist_attractions ?x .
?x ns:zoos.zoo.opened "1838-05-01"^^xsd:dateTime . 
}