There have been two World Wars, now more commonly known as World War I or First World War (from 1914 to 1918), and World War II or Second World War (from 1939 to 1945). Some consider the Cold War (from 1945 to 1991) to be World War III, but it was so unlike actual military action that this usage is highly disputable. Ypres, 1917, in the vicinity of the Battle of Passchendaele. ... 1914 is a common year starting on Thursday. ... 1918 was a common year starting on Tuesday (see link for calendar). ... Mushroom cloud from the nuclear explosion over Nagasaki rising 18 km (over 11 miles) into the air, August 9, 1945. ... 1939 was a common year starting on Sunday (link will take you to calendar). ... 1945 was a common year starting on Monday (link will take you to calendar). ... The Cold War was the open yet restricted rivalry that developed after World War II between the United States and its allies and the Soviet Union and its allies. ... 1945 was a common year starting on Monday (link will take you to calendar). ... 1991 is a common year starting on Tuesday of the Gregorian calendar. ... World War III is the name given to a hypothetical world war that would be fought between superpowers with weapons of mass destruction such as nuclear weapons. ...

At the time of the first world war, it was widely believed that never again would there be a world war like the first; consequently it was known at that time and in the years that followed as 'The Great War'.

The Great War later become known as World War One, when World War II began in 1939, following Germany's invasion of Poland led by German leader Adolf Hitler. Mushroom cloud from the nuclear explosion over Nagasaki rising 18 km (over 11 miles) into the air, August 9, 1945. ... Adolf Hitler (April 20, 1889–April 30, 1945) was the Führer und Reichskanzler (Leader and Imperial chancellor) of Germany from 1933 to his death. ...

Many people today consider the War on Terrorism, which began with the U.S. invasion of Afghanistan and eventual U.S. invasion of Iraq, as the beginning of the Third World War, or, if we are to take Cold War as the third, Fourth World War. The war on terrorism or war on terror (abbreviated in U.S. policy circles as GWOT for Global War on Terrorism[1][2]) is an effort by the governments of the United States and its principal allies, the aim of which, they have declared, is to destroy groups deemed to... The United States, with support from the United Kingdom, Australia, Canada and the Northern Alliance, invaded Afghanistan in October 2001 as part of its War on Terrorism campaign. ... For other uses of the term, see Iraq war (disambiguation) The 2003 invasion of Iraq (also called the 2nd or 3rd Persian Gulf War) began on March 20, 2003, when forces belonging primarily to the United States and the United Kingdom invaded Iraq arguably without the explicit backing of the... This article is about a hypothetical global nuclear war. ... World War IV is a name for what is commonly called the War on terrorism and is occasionally used in the United States political and policy debates that continue in the wake of the September 11, 2001 attacks. ...