what is the {start time} for {Volgograd} has {instance of} as {city} ?
Which year was Volgograd founded?
When was Volgograd founded?
SELECT ?f WHERE { ?n rdf:type ?o . ?n property:start_time ?f . resource:Volgograd rdf:type ?n . FILTER ( CONTAINS ( ?o , 'http://dbpedia.org/ontology/City' ) ) }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q914> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P31> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://dbpedia.org/ontology/City> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q914 p:P31 ?s . ?s ps:P31 ?x filter(contains(?x , 'http://dbpedia.org/ontology/City')) . ?s pq:P580 ?value}