Andreas Gursky, 1999. Minimal Rhine-river landscape. Sold for $4.3M in 2011 — set new auction record.
From Wikipedia
Rhein II is a colour photograph made by German visual artist Andreas Gursky in 1999. In the image, a river flows horizontally across the field of view, between flat green fields, under an overcast sky. Extraneous details such as dog walkers and a factory building were removed by the artist using digital editing.