Artificial quantum matter can be created and studied using ultracold atoms in optical lattices. Such quantum simulations address outstanding questions of modern condensed matter physics. In my talk I will present a quantum gas microscope that allows a microscopic view on the quantum gas in a Hubbard regime optical lattice. We study the quantum phase transition from a superfluid to a Mott insulator on a single atom level. Our novel approach opens many new possibilities for quantum simulations and quantum information applications.