World War II, or the Second World War, was a global military conflict. It began as the joining of what had initially been two separate conflicts, with the first beginning in Asia in 1937 (the Second Sino-Japanese War) and the other beginning in Europe in 1939 (the German and Soviet invasion of Poland).
The war split the majority of the world's nations into two opposing military alliances: the Allies and the Axis. It involved the mobilization of over 100 million military personnel, making it the most widespread war in history, and placed the participants in a state of "total war", which erased the distinction between civil and military resources and resulted in the complete activation of a nation's economic, industrial, and scientific capabilities for the purposes of the war effort. Over 70 million people, the majority of them civilians, were killed, making it the deadliest conflict in human history.
The Allies won the war, and as a result, the Soviet Union and the United States emerged as the world's leading superpowers. This set the stage for the Cold War, which lasted for the next 45 years. The United Nations was formed in the hope of preventing another such conflict. The self-determination spawned by the war accelerated decolonization movements in Asia and Africa, while Europe itself began moving toward integration.
The Invasion of Poland
, 1939, which precipitated World War II, was carried out by Nazi Germany
, the Soviet Union
and a small German-allied Slovak
contingent.The invasion of Poland marked the start of World War II in Europe
, as Poland's western allies, the United Kingdom, Australia and New Zealand, declared war
on Germany on September 3, soon followed by France, South Africa and Canada, among others
. The invasion began on September 1, 1939, one week after the signing of the Molotov–Ribbentrop Pact
, and ended October 6, 1939, with Germany and the Soviet Union occupying the entirety of Poland. Although the United Kingdom and France declared war on Germany soon after Germany attacked Poland, very little direct military aid was provided (see Phoney War
and Western betrayal
). Following a German-staged "Polish attack"
on August 31, 1939, on September 1, German forces invaded Poland from the north, south, and west. Spread thin defending their long borders, the Polish armies were soon forced to withdraw eastward.
was a Soviet medium tank
produced from 1941 to 1958. It is widely regarded to have been the world's best tank
when the Soviet Union entered World War II
, and although its armor
and armament were surpassed by later tanks of the era, it is credited as the war's most effective, efficient and influential design.First produced at the KhPZ
factory in Kharkov (Kharkiv
), it was the mainstay of Soviet armoured forces
throughout World War II, and widely exported afterwards. It was the most-produced tank of the war, and the second most-produced tank of all time, after its successor, the T-54/55
series.A 1996 publication showed that the T-34 was still in service with twenty-seven countries.The T-34 was developed from the BT series
of fast tanks
, and was intended to replace both the BT-5 and BT-7 tanks and the T-26 infantry tank
in service (Zaloga & Grandsen 1984:66, 111
).At its introduction, it was the tank with the best balanced attributes of firepower, mobility, and protection in existence, although initially its battlefield effectiveness suffered from the unsatisfactory ergonomic
layout of its crew compartment, lack of radios
and poor tactical employment
The Battle of the Santa Cruz Islands
, October 26, 1942, sometimes referred to as the Battle of Santa Cruz
or in Japanese sources as the Battle of the South Pacific (南太平洋海戦)
, was the fourth carrier
battle of the Pacific campaign
of World War II
and the fourth major naval engagement fought between the United States Navy
and the Imperial Japanese Navy
during the lengthy and strategically important Guadalcanal campaign
. In similar fashion to the battles of Coral Sea
, and the Eastern Solomons
, the ships of the two adversaries were rarely in direct visual
range of each other. Instead, almost all attacks by both sides were mounted by carrier or land-based aircraft
.In an attempt to drive Allied
forces from Guadalcanal
and nearby islands and end the stalemate which had existed since September 1942, the Imperial Japanese Army
planned a major ground offensive on Guadalcanal for October 20–October 25, 1942.