Short answers, pulled from the story.
The Caspian Sea is the world's largest inland body of water covering an area of approximately 371,000 square kilometers. It is nearly five times the size of Lake Superior and larger than the entire country of Germany.
The Caspian Sea separated from the open oceans around 5.5 million years ago during the Late Miocene epoch due to tectonic uplift and a fall in sea level. It is a remnant of the ancient Paratethys Sea.
The Caspian Sea is bordered by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the southwest, Iran to the south, and Turkmenistan to the southeast. These five states maintain naval forces on the sea.
The Caspian Sea is home to six sturgeon species including the beluga sturgeon and the Caspian seal which is the only aquatic mammal endemic to the region. It also contains 160 native species and subspecies of fish with about 62% being endemic.
The Convention on the Legal Status of the Caspian Sea was signed by the five littoral states at the fifth Caspian Summit in August 2018 in the Kazakh port city of Aktau. The convention grants jurisdiction over 15 nautical miles of territorial waters to each neighboring country.
The Caspian Sea reached its lowest recorded level in July 2025 falling to less than 29 meters below sea level. This decline is calculated to decrease by 9 to 18 meters during the 21st century due to global warming and desertification.