Europe's northern sea

Map The Baltic was formed 15 000 years ago as the glaciers of the last Ice Age receded. Compared with the world's oceans, it contains very little salt and can freeze over in winter. The ice melts quickly in the spring.

Its eastern spur is the Gulf of Finland, which reaches to St. Petersburg. The northern part is the Gulf of Bothnia, which stretches to within 80 kilometres of the Arctic Circle. Because of its northern latitude, the sun hardly drops below the horizon in summer.

Half of the coastland is forest. The islands are countless, some covered by coniferous trees, some just barren rocks polished by the waves.

The Baltic separates but unites the nine countries along its coastline. Clockwise from Sweden these are Finland, Russia, Estonia, Latvia, Lithuania, Poland, Germany and Denmark. Because of shared history, Norway is sometimes included, although its coastline is all to the Atlantic.

The name Baltic probably comes from balteus, the Latin for belt, because of its long and narrow shape. It is about 1600 km (1000 miles) long and its average width is 193 km (120 miles).

In most of the languages of the Baltic countries it is actually called the East Sea, even in Finnish despite the fact that it is mostly west of Finland. In Estonian it is called, more appropriately, the West Sea.

Once it was crossed by Viking longships and then the merchants of the Hanseatic League. Today its cities are connected by numerous cruiseferry lines and visited in summer by the world's leading cruise lines.