Question: What is the largest city in the country where the San Marcos River originates?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/San_Marcos_River> onto:sourceMountain ?x . ?x onto:largestCity ?uri . ?x rdf:type onto:Country}