We give a qualitative explanation of the analog of the Fermi-Pasta-Ulam (FPU) recurrence in a one-dimensional focusing nonlinear Schrodinger equation (NLSE). That recurrence can be considered as a result of the nonlinear development of modulation instability. All known exact localized solitonstype solutions describing propagation on the background of the modulationally unstable condensate show the recurrence to the condensate state after its interaction with solitons. The condensate state locally recovers its original form with the same amplitude but a different phase after soliton leave its initial region. This is the analog of the FPU recurrence for the NLSE. Based on the integrability of the NLSE, we demonstrate that the FPU recurrence takes place not only for condensate but for more general solution in the form of the cnoidal wave. This solution is periodic in space and can be represented as a solitonic lattice. That lattice reduces to isolated soliton solution in the limit of large distance between solitons. The lattice transforms into the condensate in the opposite limit of dense soliton packing. The cnoidal wave is also modulationally unstable due to soliton overlapping. This instability at the linear stage does not provide the cnoidal wave recurrence. The recurrence happens at the nonlinear stage of the modulation instability. From the practical point of view the latter property is very important, especially for the fiber communication systems which use soliton as an information carrier.1. The phenomenon of recurrence in nonlinear systems with many degrees of freedom was first observed in numerical experiment by Fermi, Pasta and Ulam [1] in 1954. The idea of Fermi was to address how randomization due to the nonlinear interaction leads to the energy equipartition between large number of degrees of freedom in the mechanical chain. The chain in [1] had a quadratic nonlinearity and included 64 oscillators supplemented with long-wave initial conditions. Instead of the energy equipartition, numerical experiments showed that after a finite time a recurrence to the initial data was achieved accompanied by a quasi-periodic energy exchange between several initially exited modes. That recurrence phenomenon became known as the Fermi-PastaUlam (FPU) problem and has been one of the most attractive subjects for numerous investigations. Later, mainly by efforts of N. Zabusky, these results were reproduced by means of more powerful computers. Besides, there were observed many other peculiarities in this problem (for details, see the original papers by Zabusky Since the discovery of the Inverse Scattering Transform (IST), which was first applied to the KDV equation by Gardner, Greene, Kruskal and Miura [5], and later to the nonlinear Schrodinger equation (NLSE) by Zakharov and Shabat [6], many aspects of the FPU recurrence became more clear. In 1971 Zakharov and Faddeev [7] proved that the KDV equation, which, in particular, can be obtained from the FPU system in the continuous limit for waves propagated in one direction...