Though it is debatable if a planet as complex and diverse as ours could ever be successfully "dominated" by a single central authority in this way, the concept of global domination has long been a popular theme in both history and fiction.
Before modern times, global domination was limited by rudimentary transportation technologies and knowledge of geography. The Roman Empire had goals of global domination, and indeed the empire was able to conquer most of the "known world" (i.e., Europe) throughout its long history. Others who succeeded in conquering large portions of the world include Alexander the Great and Genghis Khan.
French dictator Napoleon Bonaparte had sights on global domination, and is often thought of as being the quintessential global conqueror. The popular board game Risk ("The Game of Global Domination") is largely based on the campaigns of Napoleon.
In World War II, the Nazi regime of Adolf Hitler in Germany made an attempt at global domination. Hitler had ambitious plans for directly controlling all of Europe, and then hopefully obtaining a position of power that would make the rest of the countries of the world fall into allegiance of the new Nazi superpower.
During the Cold War, it was believed by anti-Communists that the Communist regime of the Soviet Union had the goal of world domination. The feeling was returned by hard-line Communists, who claimed that it was the United States that had a goal of dominating the world.
Global domination is also frequently used in science fiction as the sinister ambition of the story's villain. This in turn is often a source of parody, frequently in cartoons such as Pinky and the Brain in which a thoroughly incompetent, wimpy character tries to concoct elaborate schemes to "take over the world!" Linus Torvalds, developer of Linux, has also mock-seriously described his goals as "World domination, fast." Because of the ubiquity of Microsoft products in the computing world, company founder Bill Gates has been parodied as seeking world domination.
See also: World Government