The name of the large inland sea located between **Europe** and **Asia** is the **Caspian Sea**. It is the world's largest enclosed inland body of water, varying between freshwater and saline conditions. The Caspian Sea has significant economic importance due to its rich oil and gas reserves. It is bordered by five countries: **Russia**, **Kazakhstan**, **Turkmenistan**, **Iran**, and **Azerbaijan**. Ecologically, it supports various unique species, including the **Caspian seal**, and has been a critical area for trade and transportation throughout history.