Virtual reality and immersive environments have been proposed for a range of tasks, from training to entertainment. In this talk I will describe the development of three large-scale virtual reality devices; IVY - a six-sided immersive projective environment, MOOG - a stereo head mounted display equipped visual display coupled with a physical motion base, and the Active Desktop - a large scale immersive desk. Although each of these devices provides a compelling visual display, they do so in rather different ways and combine this visual display with other input modalities. Underlying these rather different display technologies is a common software infrastructure that allows software to be moved between the devices in a relatively straightforward manner and allows software development to take place using standard computer hardware. At York University one of the applications of virtual reality is to the generation of conflicting sensory inputs to aid in the study of basic perceptual processes with particular emphasis on the perception of self-motion and self-orientation. These are important questions on Earth where people make predictable errors in judgement given limited cues to their motion and orientation, and have applications in other domains including underwater and in outer space. I will conclude the talk with a review of some recent research into these questions and a discussion of how the virtual reality devices described in the talk (and other similar devices at York) are being used to investigate these questions in both 1g and in microgravity.