The Caspian Sea is the largest enclosed inland body of water on Earth, bordered by five countries: Russia, Kazakhstan, Turkmenistan, Iran, and Azerbaijan. It covers an area of about 371,000 square kilometers and is classified as a lake, despite its name. The sea is known for its unique ecosystem, which includes various species of fish, such as the famous sturgeon, known for producing caviar. The Caspian Sea has significant economic importance due to its rich natural resources, including oil and natural gas reserves. It also serves as a vital transportation route for goods and trade among the surrounding countries. The sea's diverse environment supports both tourism and fishing industries, contributing to the local economies.