Experts say that the general causes for WWII were the rise of nationalism, the rise of militarism, and the presence of unresolved territorial issues. But those are only broad ideas. Specific causes are said to be:

• Japan in the 1930s was ruled by a militarist government devoted to Japan's becoming a world power causing Japan to invade China. As a result this angered the United States, which reacted by making loans to China, and giving them military help. This did not help the relationship between Japan and America causing Japan to attack Pearl Harbor.
• In the other hand Germany was on the onset of the Great Depression causing the rise to power of Adolf Hitler and the NAZI party. He promised the Germans that he would pull them out of the bad times and build up a strong empire. At the same time world powers were afraid of another war, letting Germany to re-arm its army.

Most historians agree that there was no definite starting date on WWII, but most can come to one conclusion:

The Polish September Campaign also known as the "Polish-German War of 1939" is said to be the start of the war. The Polish called it the "1939 Defensive War" and The Germans knew it as the "Poland Campaign". The invasion of Poland was done by military forces of Nazi Germany, the Soviet Union and by 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 and France, declared war on Germany on September 3. The campaign began on September 1, 1939 and ended on October 6, 1939, with Germany and the Soviet Union occupying all of Poland. This was just the start of a bloody long war.

Experts agree that the turning point of WWII for the allies in the Pacific was when the US won the battle of Midway. Outgunned and outnumbered, the US Navy turned a deadly Japanese ambush into a stunning victory. Midway was not only a strategically island located in the middle of the Pacific but it helped America gain the upper hand in the battle against Japan.

The Battle of El Alamein helped restore British morale during WWII; it was a stunning victory for the British in Africa. It helped allies gain the upper hand in the dessert; this would eventually help allies attack the Axis through the South of Europe.

The victory of Stalingrad in Russia broke the German soldier's morale; the Russians were able to pull an incredible victory when all odds seemed against them. Slowly but surely the Russians pushed German troops out of Russia back into their homeland.

The conclusion of the war started when the Allies started operation D-Day. The Allies landed in Normandy on June 6, 1944. They anticipated that a successful landing would cost 10,000 dead and perhaps 30,000 wounded. After final preparations 7,000 vessels, the largest naval task force ever assembled, moved to the Normandy coast. After a long and bloody battle the Allies had taken about 10,000 casualties. The actual number was never recorded. From Normandy they progressed into Paris liberating France, eventually pushing the Germans back into Germany.

The capturing of Berlin was the final battle for the Nazi Germans. Stalin's attempt to take Berlin ahead of his allies in 1945, led to the death of 70,000 Russian soldiers. No one knows for sure why he didn't wait for the allies to attack the German capitol, but most come to the conclusion that he wanted to be known as the one that finished the Axis power. On May 2, 1945, after one of the most intense battles in human history, the guns at last stopped firing amongst the ruins of Berlin.