Baltic Sea in Estonia

© fotoman-kharkov/Getty Image

A shallow sea. Baltic Sea, Estonia

The Baltic Sea is a peculiar body of water, possessing the characteristics of seas, lakes and estuaries. Strictly speaking, it is in fact a sea and thus appropriately named, joined to the Atlantic Ocean through three straits in Denmark: the Oresund, Great Belt and Little Belt. Technically, the Baltic is classified as a brackish sea, meaning it is not entirely fresh and not entirely saline. The Baltic Sea isn’t landlocked, but it does border many countries, including Russia, Finland, Sweden, Denmark, Germany, Poland, Lithuania, Latvia and Estonia. It’s the Estonian coast featured in today’s image.

Like a lake, the Baltic is relatively shallow with an average depth of 150ft (46m). Its salinity is so low it nearly qualifies as freshwater. That’s because hundreds of rivers empty into the sea, and more fresh water falls on it in the form of rain and snow, than evaporates. The Baltic can also be described as a giant estuary, into which flow dozens of rivers. Sailors favour the Baltic because there is very little current and tide to contend with, and even when surface winds pick up, the sea remains relatively calm. Easy to navigate, a gateway to so many lands - the Baltic has been integral to trade, commerce and, inevitably, conflict in the region for centuries.