This is a simple, but very evocative natural phenomenon
which all the people living in a mountain region with a valley or,
even better a lake at the bottom can see in winter.
You get up to the mountain, exactly above the limit of the fog
and you are in the bright sun.
If you look down you have the same impression
as when you fly above the clouds by plane.
The mountain tops (in this case the Alps)
are out from the fluffy layer,
while the rest is hidden below in a grey misty separate universe.
My lake is prisoner of the fog, about 500 metres down,
and I can hardly guess its existence from here...
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This photo is part of a gallery dedicated to fog,
which can have a personal, special melancholy charm.
If you are not too afraid to walk in the mist...
click on the butterfly