World War I:
World War I (or the First World War, often abbreviated as WWI or WW1) was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously known as the Great War or "the war to end all wars", it led to the mobilisation of more than 70 million military personnel, including 60 million Europeans, making it one of the largest wars in history.It is also one of the deadliest conflicts in history, with an estimated 9 million combatant deaths and 13 million civilian deaths as a direct result of the war, while resulting genocides and the related 1918 Spanish flu pandemic caused another 17–100 million deaths worldwide, including an estimated 2.64 million Spanish flu deaths in Europe and as many as 675,000 Spanish flu deaths in the United States.
On 28 June 1914, Gavrilo Princip, a Bosnian Serb Yugoslav nationalist, assassinated the Austro-Hungarian heir Archduke Franz Ferdinand in Sarajevo, leading to the July Crisis. In response, Austria-Hungary issued an ultimatum to Serbia on 23 July. Serbia's reply failed to satisfy the Austrians, and the two moved to a war footing. A network of interlocking alliances enlarged the crisis from a bilateral issue in the Balkans to one involving most of Europe. By July 1914, the great powers of Europe were divided into two coalitions: the Triple Entente, consisting of France, Russia, and Britain; and the Triple Alliance of Germany, Austria-Hungary, and Italy. The Triple Alliance was only defensive in nature, allowing Italy to stay out of the war until April 1915, when it joined the Allied Powers after its relations with Austria-Hungary deteriorate. Russia felt it necessary to back Serbia, and approved partial mobilisation after Austria-Hungary shelled the Serbian capital of Belgrade, which was a few miles from the border, on 28 July.Full Russian mobilisation was announced on the evening of 30 July; the following day, Austria-Hungary and Germany did the same, while Germany demanded Russia demobilise within twelve hours. When Russia failed to comply, Germany declared war on Russia on 1 August in support of Austria-Hungary, the latter following suit on 6 August; France ordered full mobilisation in support of Russia on 2 August.
World War II:
World War II (WWII or WW2), also known as the Second World War, was a global war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all the great powers—forming two opposing military alliances: the Allies and the Axis. In a state of total war, directly involving more than 100 million personnel from more than 30 countries, the major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, resulting in 70 to 85 million fatalities, with more civilians than military personnel killed. Tens of millions of people died due to genocides (including the Holocaust), premeditated death from starvation, massacres, and disease. Aircraft played a major role in the conflict, including in strategic bombing of population centres, the development of nuclear weapons, and the only two uses of such in war.
World War II is generally considered to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by the United Kingdom and France on the 3rd. From late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, and formed the Axis alliance with Italy and Japan, along with other countries later on. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours: Poland, Finland, Romania and the Baltic states. Following the onset of campaigns in North Africa and East Africa, and the fall of France in mid-1940, the war continued primarily between the European Axis powers and the British Empire, with war in the Balkans, the aerial Battle of Britain, the Blitz, and the Battle of the Atlantic. On 22 June 1941, Germany led the European Axis powers in an invasion of the Soviet Union, opening the Eastern Front, the largest land theatre of war in history and trapping the Axis, crucially the German Wehrmacht, in a war of attrition.
Brainliest? Took very long ;)
