From Wikipedia "Rhein II is a photograph made by a German visual artist in 1999.  In 2011, a print was auctioned for $4.3 million, making it the most expensive photograph ever sold."

RHEIN II - The Photograph

Set between two slabs of green
the slender Rhine is seen.
If she goes from left to right
is no one's surest known.

The sky is overcast above
and no birds there are seen.
I am an admirer, sure,
of green and then the green.