Saptasindhu

(“seven seas”) In traditional mythic
geography, the seven oceans surrounding the seven concentric landmasses
(dvipas) that make up the visible world.
Each of these seven seas is composed of
a different substance. The ocean accessible to human beings is composed of
salt water, but the oceans beyond that
are composed of sugarcane juice, wine,
ghee (clarified butter), yogurt, milk, and
sweet water. Few specific details exist
about most of these oceans, but the
Ocean of Milk has a prominent place in
Hindu mythology, since it was by churning this that the gods obtained the nectar of immortality (amrta). See also
Tortoise avatar.