The 里海, or Caspian Sea, is the world's largest enclosed inland body of water, bordered by five countries: 俄罗斯, 哈萨克斯坦, 土耳其, 伊朗, and 阿塞拜疆. It is classified as a lake, despite its name, and has a unique ecosystem that includes various species of fish, such as the famous 鲟鱼. The Caspian Sea covers an area of about 371,000 square kilometers and has a maximum depth of approximately 1,025 meters. It is an important resource for oil and natural gas, making it a significant region for energy production and international trade.