  Two-dimensional (2D) materials have considerably expanded the field of
materials science in the last decade. Even more recently, various 2D materials
have been assembled into vertical van der Waals heterostacks, and it has been
proposed to combine them with other low- dimensional structures to create new
materials with hybridized properties. Here, we demonstrate the first direct
images of a suspended 0D/2D heterostructure incorporating $C_{60}$ molecules
between two graphene layers in a buckyball sandwich structure. We find clean
and ordered $C_{60}$ islands with thicknesses down to one molecule, shielded by
the graphene layers from the microscope vacuum and partially protected from
radiation damage during scanning transmission electron microscopy imaging. The
sandwich structure serves as a 2D nanoscale reaction chamber allowing the
analysis of the structure of the molecules and their dynamics at atomic
resolution.
