There is a lack of tools for exploring large non-textual collections. One challenge is the manual effort required to add metadata to these collections. In this paper, we propose an architecture that enables users to collaboratively build a faceted classification for a large, growing collection. Besides a novel wiki-like classification interface, the proposed architecture includes automated document classification and facet schema enrichment techniques. We have implemented a prototype for the American Political History multimedia collection from usa.gov. Categories and Subject Descriptors H.5.3 [Information Interfaces and Presentation]: Group and Organization Interfaces