The objective of this paper is to report on the design of semantically–rich and dynamic visual user interfaces to support exploratory interaction with the UNESCO digital library materials. The UNESCO multilingual thesaurus, which supports English, French, and Spanish, has been utilized to provide a semantic and multilingual environment where users can browse the thesaurus using word buckets, formulate queries, explore the conceptual space of their query terms and view results in a dynamic and highly interactive environment. The interface design focuses on integrating searching and browsing and multilingual elements in a visual environment where terms and retrieved documents are designed as visual objects. To facilitate users’ interaction with terms, thesauri relationships are shown using such elements as colour, size, location, and distance.