According to his estimates, the American Revolution cost $2.4 billion (all numbers are in constant FY2011 dollars), World War I cost $334 billion, World War II cost $4.1 trillion, and the Iraq and Afghanistan wars combined have cost around $1.1 trillion and growing.What were the major battles of World War 2?
Below are some of the most famous battles of World War 2. Battle of Dunkirk "Dynamo". Battle of Normandy, also known as D-Day or Operation Overlord. Battle of Stalingrad. First Battle of El Alamein.