World War II

World War II, also referred to as the Second World War and regularly shortened to WW2 or WWII, was the massive conflict that saw the first usage of nuclear weapons in war by a superpower, and the formation of the United Nations.

WWII-era technology
Several examples of World War II-era weapons and vehicles make appearances throughout the Fallout series, having survived the Great War of 2077:
 * The Master's nuclear bomb in the original Fallout appears to be modeled on Trinity, the first American atomic bomb, which was developed and tested late in the war.
 * The tank in Fallout Tactics is a modified version of a WWII-era tank, the M4 "Sherman."
 * Two WWII-era aircraft, the P-51 Mustang and B-29 Superfortress, make appearances in Fallout 3 and Fallout: New Vegas.
 * Several WWII-era weapons can be found scattered about the wastelands as well. These include the M1 Garand, the Thompson submachine gun, the M3 "Grease Gun", the Browning auto rifle, and the MG42.

Fallout and Fallout 2

 * Images depicting events in World War II appear in the Fallout intro.
 * Hitler's attempt at reinvigorating Germany's economy is also mentioned in the Fallout intro.
 * In Fallout 2, the Sierra Army Depot was originally constructed as a location for wartime equipment storage in 1942.

Fallout 3

 * In the Museum of History, there is an inaccessible World War II exhibit, the archway reading "1941-1945 American Military Might of World War II."
 * Abraham Washington is in possession of the United States' 1941 declaration of war against Germany.
 * The Anchorage Memorial is based on an iconic image from World War II.
 * The "Fat Man" is named after the atomic bomb that was dropped on Nagasaki, Japan in August 1945. Additionally, the Megaton atomic bomb is modeled after the actual bomb itself.
 * The attack on Pearl Harbor is mentioned in the Fallout 3 add-on Operation Anchorage.
 * The atomic bombing of Hiroshima is mentioned.

Fallout: New Vegas

 * Some members of the Boomers wear badges from the China Burma India Theater on their uniforms.
 * The Little Boy kit mod can be bought for the Fat Man, referencing the bomb dropped on Nagasaki.

Fallout 4

 * The Battle of Iwo Jima is mentioned and is depicted on a mural in the Museum of Freedom.
 * The male Sole Survivor's great-great-grandfather served in the U.S. Army during World War II.

Fallout Tactics

 * Both the Japanese Attack on Pearl Harbor and the atomic bombing of Hiroshima are mentioned in the intro.