Grutas de Cacahuamilpa

The Cacahuamilpa caverns open in the limestone of the Sierra Madre del Sur through an arch about forty metres wide, and inside the scale only grows. A level passage some two kilometres long runs through a chain of vast chambers, on average forty metres wide and between twenty and eighty-one metres high, hung with stalactites and filled with stalagmites. It is the best-known cave system in Mexico and still a living one: water continues to seep through the rock, and the formations are still growing. The chambers carry names drawn from their shapes, among them the Throne and the Cathedral.

The caves lie beneath the Cerro de la Corona ridge in northern Guerrero and extend into the neighbouring state of Morelos. Around ninety chambers have been identified, linked by a central gallery, of which about twenty are fully explored. Pottery fragments show the caves were used before the Spanish conquest, and indigenous peoples of the area are said to have held ceremonies in them. The name Cacahuamilpa comes from a place near the entrance and is usually translated as "peanut field". By tradition, the local population kept the caves hidden from the Spaniards; their "discovery" is credited to Manuel Sainz de la Peña Miranda, who sheltered here in 1834. In 1866 the naturalist Dominik Bilimek and the emperor Maximilian made the first biological visit, the cave was surveyed for 1,380 metres in 1922, and President Lázaro Cárdenas declared the national park in 1936. A later survey in 1987 put the length of the system at four to five kilometres.

The park covers about 2,700 hectares. Some 400 metres south lie the Grutas de Carlos Pacheco, named after a general who fought the French intervention; here water barely penetrates, and the formations stopped growing centuries ago. Two underground rivers, the Chontalcoatlán, about 8 km long and fed from the Nevado de Toluca, and the San Jerónimo, about 12 km long, run through tunnels with walls up to eighty metres high before emerging and joining to form the Amacuzac, a tributary of the Balsas. The Limontitla canyon outside the caves, where amate fig trees wrap their roots around the rock, holds a small botanical garden of the region's subtropical dry forest. Scenes from the films Macario and Tarzan and the Valley of Gold were shot in the caverns.

Getting there

The caves are in northern Guerrero, about 16 km from the silver town of Taxco de Alarcón and south-west of Mexico City. The nearest airport is Toluca's Adolfo López Mateos International Airport (TLC), about 74 km away; Mexico City International Airport (MEX) is the main international gateway for the region. Access is by road.