World War I (Aug 14, 1914 to Nov 11, 1919)

Major Participants
1. Germany, Austria, Hungary, Bulgaria and Turkey formed a group known as the Central powers.
2. England, France, Belgium and Serbia later joined by Russia and Italy, were known as the Allied powers.

Causes of War
The First World War was a consequence of
1. assassination of Archduke Franz Ferdinand of Austria,
2. initiation of war against Serbia by Austria,
3. mobilization of forces against Austria-Hungary by Russia.

The Allied forces won the war, Treaty of Versailles was signed, which curbed the power of the German Empire and led to the creation of many new countries in Eastern Europe.

World War II (1939 to 1945)

Major Participants

1. Allied Powers - Britain, Russia, USA, and France.
2. Axis Powers (central powers) - Germany, Italy and Japan.

Causes of War
The Second World War was a consequence of
1. rise of the Nazi party in Germany.
2. treaty of Versailles which was against Germany.
3. the expansion policy of Japan.

The Allied forces won the war and Germany was divided into two parts. Russia and the US became the biggest powers in the World. The end of war led to the Cold War amongst the industrialised countries.

The Cold War (1947-1991)

The Cold War refers to the period of geopolitical and economic struggle that emerged after the World War II between the US and its allies and Russia and its allies. The phase lasted from 1947 till the division of erstwhile Soviet Union in 1991. This stage was referred to as the Cold War because members of both the blocs were faced with a fear of hostile attack from its enemies. The era of cold war led to a large scale development of weapons including nuclear weapons. It also led to economic warfare and trade embargoes between nations. Japan had full support of the US and Russia supported all the erstwhile Soviet Union members. The war finally came to an end in 1991 with the dissolution of Warsaw Pact which led to the division of the Soviet Union.