what is the {start time} for {Alcatraz Island} has {heritage designation} as {place listed on the National Register of Historic Places} ?
The year ALcatraz became a heritage designation place on the National Register of Historic Places?
When did Alcatraz Island become a heritage designation  place listed on the National Register of Historic Places?
SELECT ?i WHERE { ?f property:start_time ?i . ?f property:heritage_designation resource:NRHP_listed_place . resource:Alcatraz_Island property:heritage_designation ?f }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q131354> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1435> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q19558910> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q131354 p:P1435 ?s . ?s ps:P1435 wd:Q19558910 . ?s pq:P580 ?value}