Its pretty much impossible to rule the world, esspecially today where some countries have nuclear warheads.
Look at all the great nations in history, the Roman empire, Altilla the Hun, Stalin, Hitler, Alexander The Great, Napoleon, Genghis Khan who conquered the greatest amount of land or the Turkish Ottoman Empire, they all collapsed, because they took controll and rule former nations they took, eventually the people will rise against them and ultimatly leading to the downfall. People are to proud to be taken over by a forign nation, even though in some cases they would benefit form things like free trade and travel etc. So There is no real way to rule the world, assume one would, it would not last very long, would be to difficult to keep. And other nations obviously will not just say hey take our land, for instance Russia who has nuclear warheads, how is anyone going to take over such nations? The answer is at least not by force, the only way to rule the world is if all nations on earth would form something like the UN, a united gloab, but then again there would not be a sole ruler.
