"The Copán River has wantonly changed its course to gnaw at the east side of the Acropolis.
It has devoured entire several buildings and has washed away thousands of tons of stone, leaving exposed a vertical cut a hundred and eighty-five feet in height.
Seen thus in section, ancient plaza floors and the remains of partially dismantled walls, covered by layer upon layer of later construction, testify to untold centuries of human effort."
Tatiana Proskouriakoff, An Album of Maya Architecture, p. 31
Copán River Cut
"The tomb of the founder himself (K'inich Yax K'uk' Mo') was discovered by Acropolis Project Co-Director Robert J. Sharer of the University of Pennsylvania, in his tunnel investigations of the Acropolis.
The point of departure for this research was the Acropolis Cut, gorged out by the Copán River after the abandonment of the city and exposing architectural fills and features that spanned the Copán dynasty's entire history.
We endeavored to conserve this long cross-section through a variety of measures, but prior to effecting them we needed Sharer and his colleagues and students to record and analyze the exposed features, and to place them in the larger context of the overall construction history of the Acropolis.
To do this, Sharer's Early Copán Acropolis Program (ECAP) dug a series of tunnels into the Cut atop the major plaza floors that were exposed, in order to locate, investigate, and record the earlier, buried versions of the East Court and central area of the Acropolis.
A major contribution of their work was the discovery of a royal tomb in the structure known as Hunal, which is believed by Sharer (and the author) to be the final resting place of K'inich Yax K'uk' Mo'."
William L. Fash, Scribes, Warriors and Kings: The City of Copán and the Ancient Maya, p. 84
Copan: River Cut