In this talk, after briefly reviewing the basics of quantum tunneling, we use the AdS/CFT correspondence to determine the least bounce action in a metastable AdS vacuum, identifying the most probable decay channel via the Euclidean formalism of Callan and Coleman. While the O(4)-symmetric bounce minimizes the action without gravity, the problem becomes non-trivial with gravitational effects. AdS/CFT allows us to bypass these complications. We show that the Fubini bounce in the CFT—dual to the Coleman De Luccia (CdL) bounce in AdS—has the lowest action among all finite bounces in a conformally coupled scalar theory. This establishes that, under certain conditions, the CdL bounce yields the minimal action among all large and thin-wall configurations. The conent of this talk is completely based on the paper [1].