  A 100ks XMM-Newton observation of the nearby Seyfert 2 galaxy Mrk 3 offers a
unique opportunity to explore the complexity of its X-ray spectrum. We find the
\~3-8 keV continuum to be dominated by reflection from cold matter, with
fluorescent K-shell lines detected from Ni, Fe, Ca, Ar, S, Si and Mg. At higher
energies an intrinsic power law continuum, with canonical Seyfert 1 photon
index, is seen through a near-Compton-thick cold absorber. A soft excess below
\~3 keV is found to be dominated by line emission from an outflow of `warm'
gas, photo-ionised and photo-excited by the intrinsically strong X-ray
continuum. Measured blue-shifts in the strong Fe K-alpha and OVII and VIII
emission lines are discussed in terms of the properties of the putative
molecular torus and ionised outflow.
