Abstract: A modular building structure can include a rigid chassis, vertical support components, and wall and roof component(s). The chassis can have storage compartments formed therein and can provide a foundation and floor for the structure. The vertical support components can couple to the chassis to provide a vertical framework for the structure. The wall and roof component(s) can couple to the vertical support components. The vertical support components and wall and roof component(s) can be disassembled from the chassis and stored within the storage compartments. The chassis can include a horizontal bottom panel, vertically oriented crossbeams above the bottom panel, and horizontal top panels above the crossbeams to form the storage compartments. The vertical support components can be poles and the wall and roof component(s) can be cloth. Leveling feet coupled to the bottom of the chassis can allow the chassis to be leveled with respect to the ground.