Some regions are defined by one characteristic such as a governmental unit, a language group, or a land form type, and others by the interplay of many complex features. For example, Indiana as a state is a governmental region, Latin American as an area where Spanish and Portuguese are major languages can be a linguistic region, and the Rocky Mountains as a mountain range is a land form region. A geographer may delineate a neighborhood in Minneapolis by correlating the income and educational levels of residents with the assessed valuation or property and tax rate, or distinguish others by prominent boundaries such as a freeway, park, or business district. On another scale we may identify the complexity of ethnic, religious, linguistic, and environmental features that delineate the Arab World from the Middle East or North Africa. All places on the earth have distinctive tangible and intangible characteristics that give them meaning and character and distinguish them from other places.
Geographers generally describe places by their physical or human characteristics.
The most visible evidence of global interdependence and the interaction of places are the transportation and communication lines that link every part of the world. These demonstrate that most people interact with other places almost every day of their lives. This may involve nothing more than a Georgian eating apples grown in the state of Washington and shipped to Atlanta by rail or truck. On a larger scale, international trade demonstrates that no country is self-sefficient. High population densities have developed on flood plains, for example, where people could take advantage of fertile soils, water resources, and opportunities for river transportation.