The study investigates the spontaneous formation of a two-dimensional lattice of skyrmion lines in the chiral itinerant-electron magnet MnSi. Skyrmions are topologically stable magnetic vortices with particle-like properties. The lattice forms at the boundary between paramagnetism and long-range helimagnetic order, perpendicular to a small applied magnetic field, regardless of the field's orientation relative to the atomic lattice. This experimentally establishes magnetic materials lacking inversion symmetry as a platform for new forms of crystalline order composed of topologically stable spin states. The formation of crystals is typically associated with three mechanisms: local repulsion and long-range attraction leading to liquid instability, three-particle collisions, and quantization of spins. In MnSi, these mechanisms are influenced by the lack of inversion symmetry, weak spin-orbit coupling, and the breaking of time-reversal symmetry by an external magnetic field. The study reveals that the A phase, a metastable state between the conical and paramagnetic phases, is stabilized by thermal fluctuations in an intermediate magnetic field. This phase is characterized by a hexagonal symmetry and a skyrmion density that is finite and oscillates between positive and negative values, indicating the presence of skyrmion lines with magnetization antiparallel to the applied field. The theoretical analysis supports these findings, showing that thermal fluctuations can stabilize the skyrmion crystal, which is otherwise metastable. The experimental results and theoretical calculations provide insights into the formation of novel magnetic structures in chiral magnets, highlighting the potential for topologically non-trivial spin textures in condensed matter systems.The study investigates the spontaneous formation of a two-dimensional lattice of skyrmion lines in the chiral itinerant-electron magnet MnSi. Skyrmions are topologically stable magnetic vortices with particle-like properties. The lattice forms at the boundary between paramagnetism and long-range helimagnetic order, perpendicular to a small applied magnetic field, regardless of the field's orientation relative to the atomic lattice. This experimentally establishes magnetic materials lacking inversion symmetry as a platform for new forms of crystalline order composed of topologically stable spin states. The formation of crystals is typically associated with three mechanisms: local repulsion and long-range attraction leading to liquid instability, three-particle collisions, and quantization of spins. In MnSi, these mechanisms are influenced by the lack of inversion symmetry, weak spin-orbit coupling, and the breaking of time-reversal symmetry by an external magnetic field. The study reveals that the A phase, a metastable state between the conical and paramagnetic phases, is stabilized by thermal fluctuations in an intermediate magnetic field. This phase is characterized by a hexagonal symmetry and a skyrmion density that is finite and oscillates between positive and negative values, indicating the presence of skyrmion lines with magnetization antiparallel to the applied field. The theoretical analysis supports these findings, showing that thermal fluctuations can stabilize the skyrmion crystal, which is otherwise metastable. The experimental results and theoretical calculations provide insights into the formation of novel magnetic structures in chiral magnets, highlighting the potential for topologically non-trivial spin textures in condensed matter systems.