Recently, ultracold atomic and molecular gases emerged as an ideal playground to study and emulate a variety of systems from condensed matter to nuclear physics. In many quantum phenomena, the interaction between particles plays a fundamental role, acting as a binding agent and determining the “social” structure of particle ensembles. Remarkably, in ultracold gases the interaction can be externally controlled almost at will. I will discuss some of our recent experiments based on the two types of inter- action available in ultracold gases: the contact (short-range) and dipolar (long- range)...