"Structure 6 is situated on what is now the riverbank. Maler suggested that perhaps much of the ancient site of Yaxchilan has been washed away by the river. Perhaps a lower terrace of structures, including the area arond the Masonry Pier, was once built up. However, a stairways leads from about 5 m below the plaza level up to the area northeast of Structures 6 and 7, and in ancient times someone entering there would have passed between these two structures as a gateway to the city."
Carolyn E. Tate, Yaxchilan: The Design of a Maya Ceremonial City, p. 157