A River Runs Through It
For more than a thousand years, the Usumacinta River served as a vast commercial highway linking Maya cities in the highlands of what are now the Petén region of Guatemala and the Mexican state of Chiapas to the Gulf of Mexico. Among the most prominent cities to prosper from the lucrative riverine trade in salt, cacao, cotton, obsidian, and exotic feathers were those of Yaxchilán and Piedras Negras, which rose to preeminence on the banks of the Usumacinta in the sixth and seventh centuries a.d.
These sometime rivals and erstwhile allies reached their apogee in the mid-eighth century when most of the temples, palaces, pyramids, and ballcourts we see today were constructed. In the millennium since their abandonment, both Yaxchilán and Piedras Negras have been damaged by erosion, exposure to the elements, exuberant vegetation, and the predations of looters.
In the case of Piedras Negras, further destabilization was wrought by archaeologists using outmoded excavation techniques in the 1930s. Yet the greatest threat to these extraordinary sites emerged in more recent years with the proposed construction of a hydroelectric dam on the river. So dire was the situation that in 2000, the ancient site of Yaxchilán was included on the World Monuments Watch list of 100 Most Endangered Sites. In 2002, Yaxchilán was joined by Piedras Negras, some 40 kilometers downstream. Subsequent listing of the sites in 2004 was augmented to include the dense jungle that embraces the ancient cities—rich not only in its biodiversity but in its cultural material, little of which had been documented, and all of which was at risk of being lost forever should plans to dam the Usumacinta move forward.