Geography is the study of spatial distributions and interactions of peoples, places and environments throughout the world. The discipline describes, analyzes and represents these spatial phenomena. The world is built of countries and regions that are undergoing transformations at many different spatial scales – from the local to the global. Major sub-fields include human geography, physical geography, world regions, economic geography, cultural geography, environmental geography, world population, mapping science, urban/regional planning and global conflict. What unites these various topics is the spatial perspective.