The Great Depression of the 1930s was preceded by the drying up of credit and the development of a trade war.
Hostilities initially emerged between Britain and the US, the two greatest global powers of the era.
The US moved to protect its agricultural industry by imposing tariffs on food imports.
Britain defaulted on the repayment of debts stemming from the First World War and the US responded with further import controls.
International trade collapsed and the colonial empires – headed by Britain and France – responded by creating giant trade blocs. Each excluded their rivals.
This left more recently industrialised powers like Germany, Japan and Italy out in the cold. They quickly began to look for ways to emulate their opponents.
Throughout the 1930s depression and war went hand in hand.
In 1931 Japan invaded Manchuria in north eastern China.
The US was committed to a free trade policy in China – which kept it free for US imports.
Japan’s invasion and its obvious desire to conquer the rest of China brought the two powers into direct confrontation.
Italy followed Japan on the road to war with its invasion of Ethiopia in 1935.
Hitler’s Nazi regime began to flex its muscles with the reoccupation of the Rhineland in the following year.
The lack of response from Britain and France convinced Hitler that he could expand across central and eastern Europe.
Japan relied on the US and European colonies in South East Asia for its oil, rubber and other raw materials.
Its eventual decision to attack Pearl Harbour in December 1941 followed a US embargo on oil supplies.