Germany's Alster Lake is located in the center of Hamburg, like a pearl, inlaid in the picturesque scenery of this city. More than 1,000 years ago, the Alster River flowing through Hamburg merged with the Elbe River through a low-lying grassland. As time passed, the grassland was gradually flooded, forming today's Alster Lake. Hamburgers and tourists like to walk around the lake. Every summer, swans will float on the blue waves, which is very interesting.