A metal-organic framework (MOF) with a hierarchical structure has been synthesized by the assembly of super tetrahedron units of Tb ions and organic tripodal linkers. The zeolite-like network (shown as stick models in the background) contains mesocages in which the smaller mesocages with diameters of 3.9 nm are fused to larger ones of diameter 4.7 nm (represented by space-filling models). The evacuated framework is robust and can accommodate gases or ferrocene molecules For more details see the Communication by J. Kim et al. on page 8230 ff.