Baltic Sea

The Baltic Sea is a large inland sea in northern Europe. An inland sea is a body of water that is mostly surrounded by land. The Baltic Sea lies between Scandinavia, mainland Europe, and the Baltic states. It connects to the North Sea through narrow straits near Denmark. Many countries border the Baltic Sea, including Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Poland, Germany, and Denmark. The sea has been important for travel, trade, and settlement for many centuries.

The Baltic Sea is unusual because its water is only partly salty. This is called brackish water, which means a mix of fresh water and salt water. Many rivers flow into the Baltic Sea, bringing large amounts of fresh water. At the same time, only a small amount of salt water enters from the North Sea. Because of this, the salt level is much lower than in most seas and oceans. This affects which plants and animals can live there.

The shape of the Baltic Sea was formed during the last Ice Age. An Ice Age is a long period when large parts of the Earth were covered by ice. As the ice melted, it left behind deep basins that filled with water. Over time, land movements and rising sea levels changed the connections between the Baltic Sea and the ocean. The coastline is long and complex, with many bays, islands, and peninsulas. A peninsula is a piece of land surrounded by water on most sides.

The climate around the Baltic Sea is generally cool. Winters can be cold, especially in the northern parts, where the sea may freeze. In some winters, large areas of the Baltic Sea are covered with ice. Summers are usually mild. The sea helps control temperatures in nearby coastal areas by warming the air in winter and cooling it in summer. This influence is called a maritime effect.

The Baltic Sea has supported human activity for thousands of years. Ancient peoples used it for fishing and travel. Later, it became a major route for trade. Trade means the exchange of goods between places. During the Middle Ages, cities along the Baltic Sea formed trade networks. One well-known network was the Hanseatic League, a group of trading cities that worked together. Ports such as Lübeck, Riga, and Stockholm grew as important centers.

Today, the Baltic Sea remains important for shipping, fishing, and industry. Many large cities and ports are located along its coast. However, the sea faces environmental challenges. Pollution from farms, factories, and cities has affected water quality. Pollution means harmful substances entering the environment. Because the Baltic Sea is almost enclosed and water moves slowly, pollution can remain for a long time. Countries around the sea work together to reduce damage and protect the marine environment.