Dbpedia

dbpedia provides SPARQL querying interface into structured data taken from wikipedia. For example wikipedia has a lot of train stations as articles with templates in a consistent format.

example query getting tube stations

select ?station ?farezone
where {
?station <http://dbpedia.org/ontology/fareZone> ?farezone .
?station <http://dbpedia.org/property/system> "LUL"@en .
}
limit 1000

Introducing SPARQL