Mashu Lake is a caldera lake located in Akan National Park on Hokkaido, Japan. Known for its stunning blue color, the lake is often shrouded in mist, creating a mystical atmosphere. It is one of the deepest lakes in Japan, reaching depths of about 212 meters. The lake is surrounded by steep cliffs and lush forests, making it a popular destination for nature lovers and photographers. Visitors can enjoy scenic viewpoints, hiking trails, and the unique wildlife that inhabits the area. Mashu Lake is also recognized as a UNESCO Biosphere Reserve, highlighting its ecological significance.