Thermonuclear fusion is a mighty process that powers the stars. The nuclei of lighter atoms are fusing into heavier ones, releasing plenty of energy. Since 1920, scientists have been trying to master this process for terrestrial energetics needs. Deuterium-tritium fusion was chosen, with an ignition temperature of 150 million kelvin. Many approaches to confining hot plasma have been tried. Two major ways are magnetic confinement (tokamaks and stellarators) and inertial confinement (laser-driven fusion). Fusion was achieved many times, but ignition was reached only once, in 2022, by laser fusion at NIF. ITER, the biggest tokamak being built, should start operation in 2026.