In the information retrieval context, resource collections are frequently classified using thesauri. However, the limited semantics provided by thesauri restricts the collection search and browsing capabilities. This work focuses on improving these capabilities by transforming a set of resources indexed according to a thesaurus into a semantically tagged collection. The core mechanism for building this collection is based on the conversion of the domain specific thesaurus (indexing the collection of resources) into a domain ontology connected to an upper level ontology. The feasibility of this work has been tested in the urban domain by transforming the resources accessible through the European Urban Knowledge Network into a Linked Data repository.