Complex chemical compounds found as minerals or synthesized in labs evidenced a multi-shell structure. Also, fullerenes aggregate, randomly or following a well-defined geometry, in multi-shells. The way of space filling differs as a function of the dimensions and shape of the composing small cages. In this paper an attempt to build and evaluate the stability of several fullerene aggregates is made. The results show multi-shell covalently bonded structures with stability comparable to that of C60, the reference fullerene in nanoscience. The calculations were made at the DFTB and DFT levels of theory.