Integrability of high-energy QCD

<!--HTML--><p>High-energy QCD possesses a hidden symmetry which does not exhibit itself as a symmetry of classical Lagrangian, but is only revealed on the quantum level. It turns out that the effective QCD dynamics in several important limits is described by completely integrable systems that prove to be related to the celebrated Heisenberg spin chain and its generalizations. I will explain the general phenomenon of integrability in high-energy QCD and its realization in several different situations.&nbsp; I will also overview recent attempts to use AdS/CFT correspondence to understand the origin of integrability.</p>