Ultracold quantum gases in optical lattices provide a unique platform for the study of tailored many-body systems. The realization of quantum gas microscopes marked a new era in this field. They enabled the
precision detection of single atoms on individual lattice sites and with this provide direct experimental access to non-local correlation
functions. Here we summarize the experimental progress with this new platform, where experiments evolved from textbook like studies in conceptually simple settings towards precisely controlled studies in computationally inaccessible regimes. We discuss recent results on many-body localization in two dimensions as well as on hidden correlations in Fermi-Hubbard chains.