The attack on Pearl Harbor

Isolationism is a trend in U.S. foreign policy for minimal intervention in world affairs. It has long been a foundation of U.S. foreign policy, established as a doctrine by President James Monroe in 1823

The attack on Pearl Harbor was a surprise attack by Japanese naval air forces on December 7, 1941, against the U.S. naval base at Pearl Harbor on the island of Oahu in the U.S. territory of Hawaii. Authorized by Emperor Hirohito of Japan, it aimed to destroy the Pacific fleet of the United States Navy. This attack provoked the entry of the United States into the world conflict. The annihilation of the main U.S. fleet is to allow the empire of Japan to continue to establish its "Greater East Asia Co-Prosperity Sphere" by depriving the Americans of the means to oppose it militarily; it is also a response to the economic sanctions taken by Washington in July 1941, against its imperialist policy, after the invasion of China and French Indochina as part of Japan's expansionism Shōwa. Announced in a speech by U.S. President Franklin D. Roosevelt on January 6, 1942, the Victory Program ("Program for Victory") was a war economy plan designed to enable the U.S. economy to become the "arsenal of the Allies" during World War II by producing increasing amounts of war materials. Roosevelt entrusted his Secretary of War, Henry Stimson, with the task of making it happen.

The expression D-Day, already used by the military during the preparation of the offensives at the end of the First World War1, currently designates Tuesday, June 6, 1944, the first day of the Normandy landings, marking the beginning of the Battle of Normandy in the Second World War.
D-Day, which marks the first day of the Battle of Normandy (Operation Overlord), opposing the German Wehrmacht forces (and its auxiliary troops), and the landing troops of the Allied forces of the SHAEF, is an operation taking place on the Normandy beaches in occupied France, planned for June 5, 1944, but finally postponed to Tuesday, June 6, due to the weather conditions. This military operation, named Neptune, was one of the major operations in history, both by its complications and by the importance of the means used. The idea of a military operation appeared as early as 1942, but the organization did not begin until January 1944. General Dwight D. Eisenhower was in charge of setting up the operation.

The Pacific War included the campaigns conducted from 1941 onwards in the Asia-Pacific area, as part of the confrontation between the Allies and the Japanese Empire. Japan's expansionist policy was aimed at the entire region. This war encompasses all the military operations carried out on the East Asian and Oceanic fronts of the Second World War (the Central Pacific, South-West Pacific, South-East Asian, Second Sino-Japanese War and Soviet-Japanese War theaters).
The term Pacific War is generally used in the West to refer to this set of conflicts, although not all the countries involved were bordered by the Pacific Ocean and the fighting was not limited naval operations.5 From the perspective of the empire, the Pacific War was a war of great importance. From the perspective of the Empire of Japan, this extension of the Sino-Japanese War was officially called the Greater East Asia War.  After the war, the term Fifteen Years' War came into use in Japan, tracing the conflict back to the Japanese invasion of Manchuria in 1931.





Manhattan Project is the code name for the research project that produced the first atomic bomb during World War II. It was led by the United States with the participation of the United Kingdom and Canada. From 1942 to 1946, it was directed by Major General Leslie Richard Groves of the U.S. Army Corps of Engineers. Its military component was called the Manhattan District, and the term "Manhattan" gradually replaced the official code name, Development of Substitute Materials, to refer to the entire project. During its development, the project absorbed its British counterpart, Tube Alloys.
The Manhattan Project began modestly in 1939 but eventually employed more than 130,000 people and cost nearly $2 billion U.S. in 1945, or about $26 billion in 2013. More than 90 percent of the costs were spent on plant construction and fissile material production and less than 10 percent on weapons development and manufacturing. Research and production took place at more than 30 sites, some of them secret, in the United States, the United Kingdom and Canada. As a result, two weapon models were developed during the war. In the first model, known as the cannon type, a block of uranium was projected onto another to trigger a chain reaction. The blocks were composed of uranium 235, an isotope accounting for 0.7% of natural uranium. Since it was chemically similar to the most abundant isotope, uranium 238, and had almost the same mass, their separation was difficult. Three methods were used to enrich uranium: electromagnetic separation, gaseous diffusion, and thermal diffusion. Most of these operations were carried out at the Oak Ridge National Laboratory in Tennessee.