The idea of sending video images came about the same time that radio was invented. Just as sound waves could be converted into an electronic signal, it was thought that images (light waves) could be converted into an electronic signal, sent through the air and then reconverted into picture form. A number of scientists worked on the concept, achieving partial success, and these included the Russian Zworykin, the Scotsman Baird and the Hungarian Tihanyi. The American Philo T. Farnsworth, however, made the first working television in 1927 (in fact, he coined the term "television" for the new invention). The first public demonstration of the new communications technology was made in 1934. But it was in Germany, in 1935, that the first national television broadcast service was launched.

After 1920, American art began, more and more, to develop its own distinctive forms, no longer dependent on European ideas. Edward Hopper (1882-1967) is seen as the founder of the style called American Scene Painting, after 1923. Hopper showed the loneliness and boredom of life in the big city. This was something new in art, perhaps an expression of the loss of optimism after the First World War and the sense of hopelessness that characterized the Great Depression of the 1930s. A noted woman painter of the era is Dorothea Tanning (born 1910). Married to another well known painter, Max Ernst--a German livining in exile in the USA--Tanning developed her own distinctive style related to the surrealist school (go to the EduNET Art Gallery for more on surrealist painting).

The discovery of radiation, combined with Einstein's mathematical theories, and the capability to generate massive amounts of electrical energy, made the nuclear era possible. The discovery of nuclear fission by the German Otto Hahn in 1938 led to a race in the military use of the new power source. The first nuclear reactor was put into operation in Chicago in 1942. Under Robert Oppenheimer, more than 150,000 scientists and technicians worked on the American atomic project. In 1945, the first atomic bomb was exploded in a test blast near Los Alamos, New Mexico. The first nuclear bomb was dropped on Hiroshima, Japan, on August 6, followed three days later by a second bomb, dropped on Nagasaki. Some 152,000 people were killed in the initial blasts, while more than 150,000 died later due to the effects of radiation.

On June 26, 1945, representatives of 50 countries signed the Charter of the United Nations. The United Nations or UN, with it headquarters and General Assembly in New York City, was the second major attempt to provide a forum where international disputes could be settled by negotiation rather than by armed force, and replaced the League of Nations. The League, which had really ceased to function effectively by 1938, held one last meeting in 1946 to dissolve itself.

President Harry Truman (1884-1973) took over as president of the United States after the death of Franklin Roosevelt in 1945. He stayed in power until 1953, when he was followed by Dwight D. Eisenhower (1890-1969), president from 1953 to 1961. "Ike", as he was nicknamed, was supreme leader of the British-American armies in the Second World War.

Canada