Europeana Data Model (EDM)
RDF framework for cultural heritage objects. 60M+ objects from 4,000+ European institutions.
Visit WebsiteBrowse the tree, filter it, or click any class to see just its corner of it.
Where this one tends to earn its keep.
Pan-European cultural heritage aggregation
Museum collection interoperability
Digital library metadata exchange
Cultural object linked data publishing
I haven't checked this label against the actual licence text — it's the catalogue's original guess. Check the ontology's own site before you rely on it.
Others worth a look in Media & Culture.