Culture is the set of ideas, behaviors, attitudes, and traditions that exist within large groups of people (usually of a common religion, family, or something similar). These ideas, behaviors, traditions, etc. are passed on from one generation to the next and are typically resistant to change over time. Cultures vary widely not only across the world, but even right next door. For example, if you live in America and then visit different areas of Europe, you may notice that people often get closer to each other physically in social settings - tables are often closer together at restaurants, people stand closer to each other when they speak, etc. These are examples of cultural differences.