Whilst terms such as Lebensraum are commonly associated with National-Socialist ideology of the 1930s and 40s, ideas of racial living space were in fact generated in the previous decades by an international geographic community of explorers and academics. Focusing on one of the most influential figures within this group, Sven Hedin, this is the first study that systematically connects the geographic community to the intellectual history of the development of National-Socialist ideology and genocidal practices.