States of Austria arable terrain. The other five states, in contrast, are located in the Alps and thus are comparatively unsuitable for agriculture. Their terrain is also relatively unfavourable to heavy industry and long-distance trade. Accordingly, the population of what now is the Republic of Austria has been concentrated in the former four states since prehistoric times. Austria's most densely populated state is the city-state of Vienna, the heart of what is Austria's only metropolitan area. Lower Austria ranks only fourth with regard to population density even though it contains Vienna's suburbs; this is due to large areas of land being predominantly agricultural.
States of Germany voted in favour of the merger. Federalism is one of the entrenched constitutional principles of Germany. According to the German constitution (Basic Law, or '), some topics, such as foreign affairs and defence, are the exclusive responsibility of the federation (i.e., the federal level), while others fall under the shared authority of the states and the federation; the states retain residual legislative authority for all other areas, including "culture", which in Germany includes not only topics such as financial promotion of arts and sciences, but also most forms of education and job training. Though international relations including international treaties are