Final answer:
Lightning Field is considered a photographic piece because most people have experienced it virtually through photos rather than visiting the installation in person.
Step-by-step explanation:
Lightning Field is regarded as a photographic piece, since most people have seen it through photographs rather than in person. This work of art, created by Walter De Maria in 1977, consists of a vast grid of poles erected in the desert of New Mexico and is a prime example of land art. The photographic representation of the piece has played a significant role in how the artwork is experienced globally. Due to its remote location, the encounter with Lightning Field in person is uncommon, and thus the work has largely been mediated and popularized through photographs. In these images, viewers can see the interaction between the geometric precision of the poles and the natural elements of the landscape, contributing to the piece's iconic status in contemporary art.