High-angle annular dark-field scanning transmission electron tomography has been used to reveal the three-dimensional lattice structure of the mesoporous silica MCM-48. The incoherent nature of the dark-field signal leads to directly interpretable images and three-dimensional tomographic reconstructions. The ability to manipulate the three-dimensional reconstruction allows the structure to be visualised at any orientation, revealing detail in projection or as slices not hitherto seen by direct imaging techniques.