The Caspian Sea: The world's largest inland body

In the deep waters there are large amounts of hydrogen sulfide and little oxygen, which prevents life from developing. The Caspian seal is a close relative of the Baikal seal. They migrate between the sea’s northern ice in the winter to the deep cool water of the south in the summer. Caspian Sea lampeys were traditionally carried by camel caravan from Azerbaijan. Lamprey fat was used as fuel for oil lamps.