Ultracold atoms in optical lattices have enabled experimental studies of quantum many-body physics in a clean and well-controlled manner. In particular, the advent of quantum gas microscopes has made available experimental probes ideally suited for observing spatial ordering and correlations. Recently, several groups, including ours, have realized quantum gas microscopes for fermionic atoms. Our experiment, which utilizes K-40 atoms, combines high-resolution imaging with Raman sideband cooling to achieve site-resolved fluorescent imaging. In this talk, we describe the experimental setup and the recent observation of Mott-insulating, band-insulating and metallic states of the repulsive Fermi-Hubbard model in 2D.