PETAR Caves

PETAR - the Alto Ribeira state park - covers a limestone belt in the Ribeira valley in south-west Sao Paulo, and more than three hundred caves have been mapped under it, which makes this the densest karst area in the country. Visits are guided and are mostly wet: Caverna do Diabo has a walkway and lighting, but Santana, Morro Preto, Agua Suja and Casa de Pedra involve wading rivers, ducking through low passages and getting thoroughly soaked. Casa de Pedra has an entrance porch of about two hundred and fifteen metres, among the tallest cave mouths anywhere. Above the caves the park protects a large continuous block of Atlantic forest and forms part of the South-East Atlantic Forest World Heritage listing. The Ribeira valley around it is one of the poorest parts of the state.

What's there

• Over three hundred mapped caves - the densest karst in Brazil.
• Wet guided routes - wading rivers and low passages rather than walkways.
• Casa de Pedra - an entrance porch of about 215 metres.
• Continuous Atlantic forest - the protected block above the limestone.

When to go

April to September, the dry season. Three days.

Things to know

Guides are compulsory and booked through local associations, not at the gate. Caves close entirely when rivers rise, which happens quickly after rain. You will be wet, muddy and cold; bring a change of clothes and a headtorch. Roads between the four centres are unpaved and slow.

Nearby

Iporanga and Apiai are the base towns; Caverna do Diabo is in a separate park nearby.