Although the higher order structure of condensed chromatin has been solved decades ago, the configuration of the circular minichromosme of SV40 and other DNA viruses under the nanometric, sphere-like confinement of the viral capsid has remained enigmatic. Notably, the SV40 minichromosme, released from the capsid, served in the Seventies as a paradigm for cellular chromatin. We used a unique combination of solution SAXS experiments and coarse-grained Monte Carlo simulations (done by the group of Daniel Harries) to resolve the complex structure of wt SV40 virus (in collaboration with Ariella Oppenheim). In a remarkable fit of simulations and experiments, we found that the density of the confined chromatin peaks at the center of the capsid and decreasing towards the walls (Nucleic Acid Research 2013).