• First Atomic Bomb

    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

    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

    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
    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

    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

    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

    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

    Germany surrenders
    German armed forces surrendered unconditionally at Reims, France which concludes the military engagements of World War II in Europe.
  • First Nuclear Explosion

    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

    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

    First General Purpose Electronic Computer introduced
    Charles Babbage, an English mechanical engineer and polymath, originated the concept of a programmable computer.
  • Microwave Invented

    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
    The Truman Doctrine was an American foreign policy whose stated purpose was to counter Soviet geopolitical expansion during the Cold War.
  • Presidential Succession Act

    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

    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

     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
    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

    First Junction Transistor invented
    The first bipolar junction transistors were invented by Bell Lab's William Shockley.
  • North Atlantic Treaty Organization (NATO)

    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

    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

    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
    Dwight D Eisenhower sworn in as the 34th President of the United States. He served from January 20, 1953 to January 20, 1961.