I briefly overview the motivations of recent studies of the light nuclei production in ultra-relativistic heavy ion collisions: anti-nuclei in space, and search for the critical point of the strongly-interacting matter. Then I focus on a particular recent development --- possible solution of the "snowballs in hell" puzzle --- why the nuclei with binding energies of few MeV apparently survive temperatures of around 155 MeV. Recent simulations within a hydrodynamics + hadronic transport approach, where deuterons are produced and destroyed mainly in $\pi pn \leftrightarrow \pi d$ reactions show that deuterons do not survive. They are rather created and disintegrated with approximately equal rates during a certain period of time. I show that these simulations reproduce not only deuteron spectra, but also the deuteron flow $v_2$ in PbPb collisions at 2.76 TeV. Finally, I show some preliminary results, where this approach is extended to triton and Helium-3 production.