Border history refers to the study of how political boundaries between countries have changed over time. These borders can be influenced by wars, treaties, and negotiations, reflecting the shifting power dynamics between nations. For example, the establishment of the United States and its borders involved conflicts with Native American tribes and neighboring countries like Mexico. Borders also impact cultural exchanges and migration patterns. People often move across borders for work, education, or safety, leading to diverse communities. Historical events, such as the Berlin Wall falling, illustrate how borders can symbolize division and unity, shaping the identities of nations and their citizens.