Bolivian society evolved in a highly complex and unusual environment. Although situated in tropical latitudes, it was in fact an unusual high altitude society only comparable to those few similar societies found in the Himalayas. From the earliest human settlement to the present day, a good part of its people have lived at altitudes over five thousand feet above sea level, with the majority of the population and its most advanced cultures being found at twelve thousand feet or above. While not a totally prohibitive environment, the highlands have poorer soils and much colder and drier climates, and face constraints that do not hinder the lowlands. This ecology required the domestication of plants and animals unique to the highlands and even had a dramatic impact on human physiology, as highland populations were forced to adapt to the limited supply of oxygen and quite different degrees of air pressure.