We prove that the attractor of the 1D quintic complex Ginzburg-Landau equation with a broken phase symmetry has strictly positive space-time entropy for an open set of parameter values. The result is obtained by studying chaotic oscillations in grids of weakly interacting solitons in a class of Ginzburg-Landau type equations. We provide an analytic proof for the existence of twosoliton configurations with chaotic temporal behavior, and construct solutions which are closed to a grid of such chaotic soliton pairs, with every pair in the grid well spatially separated from the neighboring ones for all time. The temporal evolution of the well-separated multi-soliton structures is described by a weakly coupled lattice dynamical system (LDS) for the coordinates and phases of the solitons. We develop a version of normal hyperbolicity theory for the weakly coupled LDS's with continuous time and establish for them the existence of space-time chaotic patterns similar to the Sinai-Bunimovich chaos in discrete-time LDS's. While the LDS part of the theory may be of independent interest, the main difficulty addressed in the paper concerns with lifting the space-time chaotic solutions of the LDS back to the initial PDE. The equations we consider here are space-time autonomous, i.e. we impose no spatial or temporal modulation which could prevent the individual solitons in the grid from drifting towards each other and destroying the well-separated grid structure in a finite time. We however manage to show that the set of space-time chaotic solutions for which the random soliton drift is arrested is large enough, so the corresponding space-time entropy is strictly positive.2000 Mathematics Subject Classification. 35Q30, 37L30. Key words and phrases. extended systems, attractors of PDE's in unbounded domains, multipulse solutions, normal hyperbolicity, center-manifold reduction, soliton interaction, lattice dynamical systems.We are grateful to A.Mielke and A.Vladimirov for useful discussions, and to WIAS (Berlin) and BenGurion University for the hospitality. 1713 1714 DIMITRY TURAEV AND SERGEY ZELIKAs a tool for finding the spatially-localized, temporally-chaotic solutions one may try, as we do it here, to look for special types of both spatially and temporally localized solutions. Thus, like Shilnikov homoclinic loop and Lorenz butterfly serve as a criterion for chaos formation in systems of ODE's [35,36,37,39], the existence of the Shilnikov homoclinic loop in the dynamical system generated by the PDE on the space of spatially localized solutions implies the space-time chaos in the extended system that corresponds to uniformly bounded solutions of the same PDE.We do not prove this principle in full generality here. Instead, we decided to show how it works for a class of Ginzburg-Landau equations with a broken phase symmetry. The main motivation for such approach is that despite a huge amount of numerical and experimental data on different types of space-time irregular behavior in various systems, there are very few rigorous mathem...