Caspian Sea
The Caspian has characteristics common to both seas and lakes. It is often listed as the world's largest lake, although it is not a freshwater lake. It contains about 3.5 times more water, by volume, than all five of North America's Great Lakes combined. The Caspian was once part of the Tethys Ocean, but became landlocked about 5.5 million years ago due to plate tectonics. The Volga River (about 80% of the inflow) and the Ural River discharge into the Caspian Sea, but it has no natural outflow other than by evaporation. Thus the Caspian ecosystem is a closed basin, with its own sea level history that is independent of the eustatic level of the world's oceans.
2001 world oil market chronology
July 24 An Iranian warship in the Caspian Sea threatens a BP oil exploration ship off the coast of Azerbaijan. This prompts BP to suspend exploration in the area. The two vessels were in the Araz-Alov-Sharg field southeast of Baku. Iran claims the field is in Iranian waters. Caspian Sea region countries have been unable to agree on a division of the Sea. (NYT)