Rückenfigur

the disinterested observer at the river under the train bridge

unseen are the river and the bathers

David Caspar Friedrich was instrumental in transforming landscape in art from a backdrop subordinated to human drama to a self-contained emotive subject. Friedrich's paintings commonly employed the Rückenfigur - a person seen from behind, contemplating the view. The viewer is encouraged to place himself in the position of the Rückenfigur, by which means he experiences the sublime potential of nature, understanding that the scene is as perceived and idealised by a human. Wikipedia