All the physical feature that characterize the surface of a geographic region constitute its topography. Some surface features such as navigable rivers and flat plains facilitate travel and contact with others. In contrast, treacherous mountain ranges and large bodies of water can discourage contact and cultural change. Cultures isolated by impassable mountains or large bodies of water will be less exposed to the cultural of other people . That is why cultural change tend to occur more slowly in isolated cultures than in cultures not isolated in such a manner.