Americans learned of the developments in Europe and Asian through reporting in America’s media: newspapers, newsreels and radio. In Europe, Germany was seeking domination through a series of successful invasions (Poland, Belgium, France, etc.) as well as extermination of “undesirable” populations (Jews, ethnic minorities, homosexuals and others) in what would become known as the Holocaust. Meanwhile, Japan was seeking domination in Asia and the Pacific, through a series of battles in China and Southeast Asia. Italy was the only European country to side with Germany and was itself seeking to expand its dominance, invading Ethiopia. These countries would be known as the Axis; their opponent the Allies.
It’s estimated 60 million people died in World War II.