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First Atomic Bomb
The development of the first atomic bomb is signed into an agreement between the Prime Minister of Great Britain, Winston Churchill, and President Franklin D Roosevelt. -
Jefferson Memorial
The Jefferson Memorial in Washington DC is dedicated on the 200th anniversary of Thomas Jefferson's birth by President Franklin D Roosevelt. -
D-Day / Operation Overlord
Allied soldiers stormed the beaches of France to begin the World War II invasion of Europe that would lead to the liberation of Paris. Operation Overlord gained footing quickly, pushing through the Atlantic Wall in the largest amphibious military operation in history. -
The Cold War
The Cold War was a period of geopolitical tension between the United States and the Soviet Union and their respective allies which began following World War II. -
Battle of Okinawa
The Battle of Okinawa, codenamed Operation Iceberg, was a major battle of the Pacific War fought on the island of Okinawa by United States Army and United States Marine Corps forces against the Imperial Japanese Army. It ended June 22, 1 945 and was the last major battle of World War II. -
Harry S Truman
Truman sworn in as the 33rd President of the United States. He served from April 12, 1945 to January 20, 1953. -
Death of President Roosevelt
President Roosevelt dies suddenly. Vice President Harry S Truman assumes the presidency and role as commander in chief of World War II. -
Germany surrenders
German armed forces surrendered unconditionally at Reims, France which concludes the military engagements of World War II in Europe. -
First Nuclear Explosion
The first nuclear explosion occurred when a plutonium implosion device was tested at a site located 210 miles south of Los Alamos, New Mexico. -
World War II ends
Formal surrender documents were signed aboard the USS Missouri, designating the day as the official Victory over Japan Day. -
First General Purpose Electronic Computer introduced
Charles Babbage, an English mechanical engineer and polymath, originated the concept of a programmable computer. -
Microwave Invented
American engineer Percy Spencer is credited with inventing the modern microwave oven after World War II from radar technology developed during the war. -
The Truman Doctrine
The Truman Doctrine was an American foreign policy whose stated purpose was to counter Soviet geopolitical expansion during the Cold War. -
Presidential Succession Act
The Presidential Succession Act is signed into law by President Truman. It is a federal statute establishing the presidential line of succession. -
Central Intelligence Agency
The CIA is established as a civilian foreign intelligence service of the federal government of the United States. It was created to create a clearinghouse for foreign policy intelligence and analysis. -
Transistor invented
The transistor was successfully demonstrated at Bell Laboratories in Murray Hill, New Jersey. The three individuals credited with the invention of the transistor were William Shockley, John Bardeen and Walter Brattain. -
The Marshall Plan
The Marshall Plan, also known as the European Recovery Program, was a US program providing aid to Western Europe following the devastation of World War II. -
First Junction Transistor invented
The first bipolar junction transistors were invented by Bell Lab's William Shockley. -
North Atlantic Treaty Organization (NATO)
The North Atlantic Treaty Organization, also called the North Atlantic Alliance, is an intergovernmental military alliance between 28 European countries and 2 North American countries. The organization implements the North Atlantic Treaty. It states that any attack against one nation would be considered an attack against them all. -
Korean War
The Korean War was a war between North Korea and South Korea. The war began when North Korea invaded South Korea following clashes along the border and insurrections in the south. The war ended unofficially on July 27, 1953. -
First Hydrogen Bomb Detonated
The United States successfully detonated "Mike", the world's first hydrogen bomb, on the Eniwetok Atoll in the Pacific Marshall Islands. -
Dwight D Eisenhower
Dwight D Eisenhower sworn in as the 34th President of the United States. He served from January 20, 1953 to January 20, 1961.