Stockholm is located on Sweden's east coast, where the freshwater Lake Mälaren — Sweden's third-largest lake — flows out into the Baltic Sea. The central parts of the city consist of fourteen islands that are continuous with the Stockholm archipelago. The geographical city center is situated on the water, in Riddarfjärden bay. Over 30% of the city area is made up of waterways and another 30% is made up of parks and green spaces.