Warmatrix

A tank is an armored fighting vehicle. Its tactical value is a combination of guns for attack, armor for defense and mechanized power for mobility. It is at its best in open terrain, in offensive operations.
Tanks had been envisioned since the Middle Ages, but had to wait until the invention of the internal combustion engine and continuous alias caterpillar tracks to become reality. The power of the engines is necessary to push them forward; the tracks distribute their heavy weight and give them grip even on soft soil. Though land vehicles, the earliest tanks were paradoxically developed by the British Royal Navy. Hence its name, 'tank', which stood for a ship that resembled a water carrier, though most were called 'land ships' by the people who saw them. The first model to see combat was the Mark I, a few dozen of which fought in the Battle of the Somme. This was a big vehicle, manned by a crew of 8 inside a very hot hull filled with exhaust gases. It was armed with several machine guns, with tracks all around the carriage, capable of a top speed of 6 kilometers per hour. The early tanks were used to break through barbed wire defenses and strengthen the advance of infantry, still the main weapon in World War I. Tanks gave the British and French armies only a small edge in the war, because they were still in their infancy.
In the last two years of the Great War and in the interwar period tanks were further developed. Armor, speed, reliability and crew comfort were improved and all but the lightest tanks were equipped with a cannon as the main weapon. The machine guns were retained as secondary weapons to fend off infantry at close range. The tracks were mounted on two rows of wheels at the bottom, instead of all around. Suspension systems were improved, greatly increasing cross-country speed. Some tanks were equipped with rotating turrets, to be able to fire in all directions, a feature that became universal during World War II. All this gave the tank its classic shape.
In World War I and later tanks were classified in three broad categories: light, medium and heavy. 'Light' tanks focused on speed an maneuverability. These were used to exploit weaknesses in enemy defenses and disrupt enemy communications and supply lines behind the frontlines. 'Heavy' or 'assault' tanks stressed armor and firepower. These worked together with infantry to break through enemy defenses. 'Medium' tanks occupied the middle ground. By start of World War II the average medium tank weighed around 20 tons, carried a 50mm gun, had a three men crew and could attain speeds of 40 kilometers per hour.
The most important tank innovations of World War II were not technical, but organizational. Some leading military theorists proposed to group tanks in specialized units, rather than dispersing them through the ranks of the infantry. Supported by motorized infantry and artillery and also aircraft, this allowed the tanks to exploit their mobility. When World War II broke out, the Germans proved that they had learned these lessons by far the best. Though their tanks on average were inferior in both quality and quantity than those of their enemies, they coordinated their attacks through radio and outmaneuvered most opponents. The German 'Blitzkrieg' doctrine stated that the tanks should punch through defenses, race deep into the enemy rear, bypass strongpoints and disrupt communications and supply lines. Soon the enemies of Germany, shocked by the success of the Wehrmacht, adopted similar tactics.
World War II was the zenith of the tank era; worldwide more than 300,000 were produced in that period. Many famous tanks, like the Soviet T-34 and the German Tiger and Panther, originate from that period. Tanks evolved rapidly during the war. Torsion-bar suspension was applied to smoothen the rides; the Soviets came up with sloping armor; firepower and armor were upgraded continuously. Specialized tanks appeared, among them flame throwers, mine clearers and bridging vehicles.
The arms race in World War II made tanks steadily heavier. By 1945 CE the average medium tank weighed 40 tons and carried a 75mm or 85mm gun. Several tank designs went through the roof, like the German Panzer VIII Maus, weighing 188 tons. These monsters proved too costly, too slow, too wide and heavy for roads and bridges; they never got beyond the prototype or even drawing board stage. Nonetheless by the end of the war light tanks were starting to become rare, as their speed and maneuverability proved no match against superior firepower. This trend continued and widened after the war. Eventually the different categories of tanks coalesced into a single one, the main battle tank. These remain the dominant category until this day.