"One reason that Eurasian civilizations dominated the globe is because they came from a continent that was broader in an east–west direction than north–south (...) a modelling study has found evidence to support this 'continental axis theory'. Continents that span narrower bands of latitude have less variation in climate, which means a set of plants and animals that are adapted to more similar conditions. That is an advantage, says Diamond, because it means that agricultural innovations are able to diffuse more easily, with culture and ideas following suit. As a result, Diamond's hypothesis predicts, along lines of latitude there will be more cultural homogeneity than along lines of longitude. (...)" - Amira

"The researchers found that if a country had a greater east–west axis than a north–south one, the less likely it was for its indigenous languages to persist. The relationship isn't straightforward, but the model suggests that Mongolia, which is about twice as wide as it is tall, would have 5% fewer indigenous languages than Angola, which is roughly square. Meanwhile, Peru — about twice as tall as it is wide — would be predicted to have 5% more persistent languages than Angola. (...) Greater cultural diversity is also known to be associated with outcomes such as lower levels of economic growth and higher probabilities of violence. (...) [The study] further supports the idea that human history and cultural evolution are governed by general ecological and biogeographical rules." - Amira