Visualizations based on incomplete primary material lead to a recognised danger that 3D models can be misinterpreted as a totally accurate replica of reality. Good practice in creating reconstructions of non-extant architecture requires meticulous documentation of the process and its outputs. However, unless the research sources and methods are made explicit, the danger of mis-reading visualized data remains. This paper describes the development of software that allows research sources, methods, and interpretation to be added as multimedia annotations to a 3D scene. All real-world and digital objects are semantically described and spatially placed within the scene. The software is built on a CIDOC-CRM export-compatible data model and presents a novel collaborative interface for simultaneously creating annotations in an intuitive visualization environment using remote tablet PCs. The development of a life-size, stereo visualization of this lost architecture, with spatialised semantic annotations, will enhance understanding of this hugely significant event in history.