Measurements and models of global geophysical parameters such as potential fields, seismic velocity models and dynamic / residual topography are well represented as 2D coloured / contoured maps. However, as teaching aids and for outreach, they offer little impact. Modern 3D-printing techniques help to visualize these and other concepts that are difficult to grasp, such as the intangible structures in the deep Earth. We developed a simple method for portraying scalar fields by 3D printing modified globes of surface topography, representing the parameter of interest as additional, exaggerated topography. This is particularly effective for long-wavelength (>500 km) fields. The workflow uses only open source and free-to-use software, and the resulting models print easily and effectively on a cheap (<300 GBP, 400USD) desktop 3D-printer. We have printed 3D representations of different scalar fields, including models of the surface topography of rocky planets, which can be used in outreach events. These objects are powerful to explain the importance of plate tectonics in shaping a planet. The workflow was extended to 3D scalar fields by analogy to Russian nesting dolls, where the audience can remove shallower layers to see how structures change with depth. We applied this to global seismic tomography models resulting in prototypes of “seismic matryoshkas” (see Figure). The tactile nature of these objects ensures that anyone, including the visually impaired, can explore the structures present deep within our planet