We review several experimental aspects of ultracold bosonic and fermionic quantum gases in optical lattices. After introducing fundamental aspects of optical lattices, we use the superfluid-Mott insulator transition of ultracold bosonic quantum gases in optical lattices, to highlight the physics of strongly correlated quantum systems. We discuss the coherence properties and recent measurements of the shell structure of in the Mott insulating phase. Furthermore, we show how quantum noise correlations can be used to detect quantum phases of strongly correlated bosonic and fermionic quantum gases in optical lattices.