A border is a defined line that separates two areas, often countries or regions. It can be marked by physical barriers like walls or fences, or simply by signs indicating the change in jurisdiction. Borders can be natural, such as rivers or mountains, or artificial, created through treaties or agreements. They play a crucial role in politics, trade, and immigration. Borders can also influence culture and identity, as they often determine the languages spoken, customs practiced, and laws enforced in a region. People living near borders may experience unique interactions with neighboring areas, leading to both cooperation and conflict. Understanding borders is essential for studying global relations and geography.