Cantons of Switzerland the canton of Schwyz. Six of the 26 cantons are traditionally, but no longer officially, called "half-cantons" (, , , ). In two instances (Basel and Appenzell) this was a consequence of a historic division, whilst in the case of Unterwalden a historic mutual association, resulting in three pairs of half-cantons. The other 20 cantons were — and in some instances still are — though only in a context where it is needed to distinguish them from any half-cantons, typically termed "full" cantons in English. The historic half-cantons, and their pairings, are still recognizable in the first article of the
Geography of Switzerland of the range, in the cantons of Vaud, Neuchâtel and Bern. Switzerland has 6% of all freshwater reserves in Europe. The country shares five river basins and some of the largest lakes in western Europe with its neighbours. It is the source of several major European rivers that ultimately flow into the North Sea (Rhine), into the Mediterranean Sea (Rhône), into the Black Sea (Inn, through the Danube) and into the Adriatic Sea (Ticino, through the Po and Rom through the Adige). Most of the great Swiss rivers, being in their origin mere mountain torrents, tend to overflow their banks.