Studying confining gauge theories on a circle can provide answers to some of the deepest questions about QCD. In this talk, I start by summarizing the main characteristics shared by the compactified theories and their four dimensional cousins. Next, I show that the glueball spectrum of the compactified theories is much richer than what have been thought before. In particular, new nonperturbative scales and glueballs emerge in the deep IR regime of the theory. I discuss the spectrum in the context of super Yang-Mills and show that the lightest glueball states fill a chiral supermultiplet with doubly-nonperturbative binding energy. I end with possible implications of these findings for the four dimensional gauge theories.