Interactive exploration of extremely large geometric models is becoming a fundamental capability in many application areas, including games, CAD, virtual prototyping, geoviewing, and scientific visualization. Thanks to fundamental advances in 3D modeling, simulation, and data capture technologies, 3D model complexity is continuing to increase. Handling such massive models presents important challenges to application developers. This is particularly true for highly interactive 3D applications, such as visual simulations and virtual environments, with their inherent focus on interactive, low-latency, and real-time processing. This seminar will provide a short overview of our recent (and not so recent) work in enabling technology for massive surface and volumetric model explorations, with a focus on improving application scalability through specialized adaptive streaming, compression, and GPU rendering methods for surfaces and volumes, and improving quality of experience through interactive 3D environments based on novel 3D display technology.