RKB Explorer is a Semantic Web application that is able to present unified views of a significant number of heterogeneous data sources regarding a given domain. We have developed an underlying information infrastructure which is mediated by ontologies and consists of many independent triplestores. Our current dataset totals many tens of millions of triples, and is publicly available through both SPARQL endpoints and resolvable URIs. To realise the synergy of disparate information sources, we have deployed tools to identify co-referent URIs, and devised an architecture to allow the information to be represented and used. This paper provides a brief overview of the RKB Explorer application, the underlying infrastructure, and a number of associated tools for both knowledge acquisition and publishing.