Piedras Negras lies on a wide bank of the Río Usumacinta, the longest river in Central America. It is about as far away in the Mesoamerican wild as you can possibly be—surrounded on all sides by the thick forests of the Sierra del Lacandón, with barely a road in sight.
Piedras Negras was founded around A.D. 300 and fought with Yaxchilán  (40 km upstream on the Mexico side) over control of the river route for much of its history.
Today, Piedras Negras is threatened by the proposal to build a hydroelectric dam some 30 miles downstream on the Río Usumacinta at Boca de Cerro. If this happens, 18 archaeological sites would be lost underwater.
Archaeologists have uncovered eight sweat baths, with fire hearths lined with potsherds, benches, and floors equipped with drains. The remains of Russian Maya scholar Tatiana Proskouriakoff (1909–1985), who studied Piedras Negras extensively, are buried under the floor of Structure J-23 in the Acropolis (a twin-palace) near Group F.
Many fine stelae were placed before the temples here, and a few of Piedras Negras’s inscriptions mention future cycle endings.
Piedras Negras is very remote; there are no set hours and entrance is free. The easiest way to visit the site is to sign up with a tour that specializes in trips here, like Maya Expeditions (www.mayaexpeditions.com ), or through the Posada Maya (tel. 502/7861-1799, US$20) in Bethel.
There is a riverside campsite on a sandy beach just a few hundred meters downstream from Piedras Negras; bring your own gear. In Bethel, you can book a guided overnight camping trip to the ruins and river (US$125).
This is one of the most remote Maya sites in the entire Mundo Maya, on the far western panhandle of the Petén , so getting there is part of the experience. Only about 200 tourists make the trip annually, so don’t expect crowds. Access is from Bethel  or Frontera Corozal . Visitors then head downstream by boat to Piedras Negras, which is beyond Yaxchilán .
For more travel information on things to see and do at Piedras Negras and in the surrounding area, please visit the Piedras Negras section of our Moon Guatemala travel guide .