Mälaren is the third-largest lake in Sweden, located in the central part of the country. It stretches approximately 120 kilometers and is known for its beautiful scenery and rich biodiversity. The lake connects to the Baltic Sea through the Stockholm archipelago, making it an important waterway for transportation and trade. Surrounding Mälaren are several cities, including Stockholm, Uppsala, and Västerås. The lake is popular for recreational activities such as boating, fishing, and swimming. Its shores are dotted with historical sites, including castles and ancient ruins, reflecting the region's cultural heritage.