Accurate estimates of the spatial distribution and of the velocity field of gas and dust surrounding accreting super-massive black holes is key to a number of astrophysical problem, from AGN feeding and feed-back to the synthesis of the Cosmic X-ray Background. X-rays observations allow to probe these quantities directly by studying the structural changes (column density, ionization) undergone by hot gas along the line-of-sight, as well the Compton-scattering of the primary AGN emission in high-energy X-ray spectra of nearby, heavily obscured AGN. In this talk we report the results of a NuSTAR, Suzaku, and XMM-Newton monitoring campaign performed in 2014-2015 on one of the X-ray brightest objects of this class: Markarian 3. The results of this campaign allow an unprecedented 3-D reconstruction of the gas and dust cloud configuration surrounding this AGN.