Question: Which structure in downtown Chicago opened most recently?
Answer(s):
answer: Willis Tower

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:location.location.containedby ns:m.01_d4 .
?x ns:architecture.structure.opened ?num .
}
ORDER BY DESC(?num) LIMIT 1