Borders mean different things to different nations. For decades, the USA believed in "manifest destiny," pushing its western border until it reached the Pacific. To the Romans, borders were trophies, trade routes and the abstract ideas of what it meant to be called a Roman. Perhaps no time best illustrated the importance of borders and their meaning than the Cold War, when the communist East and the capitalist/democratic West pressed hard on their borders, causing anxiety up and down the fringe of the Iron Curtain.
A country's borders, in combination with its geography, determines how well it can trade, how well defended it is, what natural resources are available and the size of the population it is capable of supporting. As a result, nations guard their borders, seeing every move of their neighbors as a potential threat. Border crossings can be friendly affairs where commuters travel every day, or they can be militarized death traps through which none shall pass. Border crossings happen by accident, and sometimes they happen deliberately, to trade spies or to trade favors between monarchs. Some borders are disputed, while others have been set in stone for centuries, sometimes literally. Do you think you know the world's many border crossings? It's time to find out how worldly you are!