There is evidence that the human
species has evolved from the oceans.
Our veins are filled with salt-water.
Our lungs appear to be formed
from a system of gill-like slits.

Slowly, over a long period of time,
our mammalian ancestors emerged
from the oceans to populate the land.

Some mammals, such as whales,
were forced to return to the ocean,
presumably because of their great size
which ultimately became more of a liability
on land than in the buoyancy of the sea.

Many species of fish eventually return
to the streams where they were born.
Some fish, such as salmon,
after swimming thousands
of miles over a virtual lifetime,
return to the exact spot
where there eggs were deposited and hatched.

Humans have remained on land, and have
roamed the oceans only with the assistance
of hydro-navigational equipment.

In all races and cultures, humans find the need
to return to their place of birth, to where they
grew up as a child, where they spent their
formative years.

This tendency gets stronger with age, and
probably represents the origins of what is
commonly referred to as nostalgia.

It is quite possible that the sensations and
feelings associated with nostalgia are a
by-product, or side-effect of this most
basic instinct, an inherent tendency
to return to our beginnings, directly
traceable to the millions of years which
we spent as creatures of the oceans.