In this research we investigate to what extent explicit semantics can be used to support end users with the exploration of a large heterogeneous collection. In particular we consider cultural heritage, a knowledge-rich domain in which collections are typically described by multiple thesauri. Many institutions have made or are making (parts of) their collections available online. The cultural heritage community has the ambition to make these isolated collections and thesauri interoperable and allow users to explore cultural heritage in a richer environment.