“Six photographs of unremarkable industrial landscapes in Passaic, New Jersey depict evidence of man-made history, yet the title of “monument” seems ironic. Stripped of any apparent artistic agenda, the images appear photojournalistic—without an accompanying news article to inform our perception. Smithson was perpetually intrigued by suburbia; in its sameness he saw a version of eternity defined by formal repetition rather than temporal longevity. By framing the mundane sites as “monuments,” Smithson challenges the conceptions of aesthetic merit and historical significance.  Monuments of Passaic exists as three manifestations: a published article in Artforum, a photowork, and a photographic series.” [credit]

Robert Smithson – A Tour of the Monuments of Passaic (PDF)

He drew further attention to site-specificity and the passage of time via his walk along the river and industrial sites.