SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/San_Marcos_River> <http://dbpedia.org/ontology/sourceMountain> ?x . ?x <http://dbpedia.org/ontology/largestCity> ?uri . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Country>}
What is the largest city in the country where the San Marcos River originates?
SELECT DISTINCT ?b WHERE { resource:San_Marcos_River property:source_mountain ?d . ?d rdf:type ontology:Country . ?d property:largest_city ?b }
New York City
The largest city in the country where San Marcos River originates is [New York City].
The largest city in the country on the San Marcos River starts from is [New York City].
The largest city of the country which is the source mountain of San Marcos River  is [New York City].
The largest city in the country, the source of the San Marcos River, is [New York City].