Germany's Panzer I - the worst imported tank of the Spanish Civil War

The Treaty of Versailles forbade Germany from developing tanks. However, by 1926 the German government had contracted with multiple manufacturers to produce experimental heavy tanks, the Grosstraktor. By 1930, they decided to also build a light machine-gun armed tank for training.

The Italian CV tankettes - the baby tanks of the Spanish Civil War

The Italian contribution to the Fascist incursion into Spain were the CV 33 and CV 35 tankettes (CV standing for carro veloce, or “fast car”). Tiny, lightly armored two-person vehicles armed only with machineguns, they were the result of one of the competing philosophies about armored vehicles in the 1920s and 30s and indirect descendants of the Ford 3-ton tank. 

The BT-5 - the fast tank that served in the Spanish Civil War

Developed from John Walter Christie’s designs, the BT series of tanks were the fastest tanks in the Soviet garage.

T-26 - The primary Communist tank of the Spanish Civil War

Developed from the British Vickers 6-ton tank, the Soviet T-26 was the USSR's standard light tank of the 1930s. More than 11,000 were built over a decade.