A structure is provided having a floor, and a canopy made from a flexible, substantially air-impermeable material and having a tubular rib. The canopy has an air inlet port by which the interior of the tubular rib can be connected to a source of compressed air, and is movable by the supply of compressed air from a collapsed state in which the tubular rib is deflated to an inflated state in which the tubular rib is inflated and supports the canopy in such a way that the canopy encloses an interior space above the floor and forms a roof and side walls of the structure. The floor has three substantially rigid floor panels which may be arranged together to form a substantially planar floor, or connected together to form the base and sides of a container in which the canopy can be stored when in the collapsed state.