The word "tokamak" is of Russian origin and means "toroidal chamber and magnetic coils." This magnetic confinement system holds plasma in magnetic fields of toroidal shape. The first tokamak, the T-1, started operation in 1958 in Russia, and since then the greatest advances in thermonuclear fusion research have been achieved with tokamaks. The largest tokamak of its time, JET, with a plasma volume of 80 m³, came closest to the scientific breakeven point in 1997, when it achieved Q = 0.67. There are over fifty tokamaks around the world, to name the most important ones: JET, JT-60SA, EAST, WEST, or TFTR. The biggest tokamak in the world, ITER, is now being built in Cadarache, France.