Everyone has to be somewhere. Is that too obvious? Not to me as a writer. I feel an obligation to help the reader imagine the setting. The geography affects the ease or difficulty of movement. The flora, fauna and weather contribute to a sense of environment.
The Andes shape the use of South American countries. They are a barrier running down the interior of the nation. If you are wealthy, the range is something to be flown over. If you are not-so-rich, the bus trip can take days, or longer if landslides block the road. The isolation of the Incas and other native groups helped them evade the Spanish conquest. Native cultures still flourish at high altitudes. In Benny Goldfarb, Private “I”, the protagonists travel into the interior of Colombia. The detail of the story almost demanded the inclusion of a native group. In this case, the Paez tribe provides another point of view in Colombian society.