In this paper, we present our work with the VisionDome, a fully immersive, single-projection, 3D display device. As contrasted to other immersive systems, the VisionDome does not require any equipment for the user to wear, is relatively inexpensive and portable, and can support multi- user collaboration. In this paper we describe the technical specifications of the VisionDome, as well as the problems encountered when viewing inside this immersive device. As a case study, we show the results of incorporating the VisionDome within GeoViz, which is a visualization software package for geophysical and geological data. We show how users of GeoViz are successfully finding new locations for oil more rapidly based on the immersive display of seismic and other data that they are viewing from inside the VisionDome.