Institutional seats of the European Union are based in Luxembourg City along with the European Investment Bank. The Economic and Social Committee and the Committee of the Regions are entirely based in Brussels while the European Central Bank is based in Frankfurt and Europol is the only agency to have its seat fixed by the treaties, in The Hague. Separately, the Treaty of Nice establishes Brussels as the venue for all formal summits of the European Council after 2004. However some extraordinary sessions are sometimes held outside the city. The European Council's seat is however fixed by a declaration rather than a protocol, meaning it is
Central European Highlands Central European Highlands The Central European Highlands, in a broad sense, comprise the high mountains of the Alpine Mountains and the Carpathian Mountains systems along with mountainous ranges of medium elevation (between about 1000 and 2000 m a.s.l.), e.g. those belonging to the Bohemian Massif, still prevailingly of mountainous character. Both types of mountains act as ”water towers”. Their high elevation brings about high precipitation and low evaporation, and the resulting surplus of water balance feeds large European rivers and other important water sources. Beside the mountains, large areas of Central Europe are occupied by highlands or peneplains of lower