Radar was developed in World War Two. Radio waves were used to detect aircraft before they could been seen or heard. Atomic weapons . In August 1945, America dropped two atomic bombs on Hiroshima and Nagasaki, Japan. The bombs ended the war, but demonstrated the destructiveness of modern technology.
Scientists say many nations now have enough nuclear weapons to destroy the entire planet.
There have been no major wars since World War Two. The world has come to understand that we have the technology to destroy ourselves. Fifty years ago, an evil man used technology to remake the world. He almost succeeded. Today we have technology that wasn't available to Hitler, but we are also aware of the danger.