*Furnas do Bom Jesus* translates as caves of the Good Jesus, a name borrowed from the canyon that threads through the middle of the protected area. The park covers 2,069 hectares in the municipality of Pedregulho, in the far northeast of São Paulo state within the Ribeirão Preto mesoregion, 442 kilometres from the state capital. Everything here drains into the Córrego do Pedregulho. The topography is deceptively simple from above and complicated once you are in it: medium hills with flat tops, slopes seamed with small canyons, and watercourses that gather on the plateau before throwing themselves off the edge. Viewpoints sit at the Santa Luzia and Taquari centres, with the park's administrative headquarters at Santa Luzia. The trails that reach the waterfalls are steep and generally rated medium to hard.

Ecologically, this is a seam. Cerrado — the vast, fire-adapted savanna of Brazil's interior — pushes up against fragments of Atlantic Forest, and the park protects both. The distribution follows water with almost diagrammatic clarity. On the interfluves, between drainages, you get cerradão, open cerrado and meadow. Down in the valley bottoms, continuous gallery forest runs unbroken along the streams. On the canyon slopes and walls, where the dry season bites hardest, the trees are deciduous and drop their leaves rather than fight for moisture they cannot get. Marshes, flooded meadows and high meadows fill in the rest. Ipê and jacaranda flower against the rock, jequitibá and peroba hold the older stands, and bromeliads and orchids colonise whatever surface will have them.

Almost all of the natural cerrado on the flat chapada tops and the gentler slopes was cleared — first for coffee, then for pasture. That happened across the whole biome; the cerrado has been drastically modified by human hands, and this corner of São Paulo was no exception. What makes Furnas do Bom Jesus valuable is partly what the farmers could not reach. The steepest ground, the canyon walls, the places a plough could never go, kept remnants of the original forest through the whole clearing era. Around them, on the abandoned coffee ground, the cerrado is coming back. Regeneration on this scale is slow and imperfect, and a recovering savanna is not the same thing as an untouched one — but the seed source survived, and that is the part that cannot be manufactured.

The park exists because of state decree 30.591, signed on 12 October 1989. A second decree, 31.644 of 31 May 1990, declared the land to be of social interest for the purposes of expropriation — the legal machinery required to convert private coffee country into a public reserve. It is classified as a fully protected conservation unit, charged with preserving its ecosystems, its geomorphological sites and its natural landscapes while still supporting research and public visits. Universities took the invitation seriously. The University of São Paulo among others runs scientific work inside the park, which means the canyon is studied as well as photographed.

The climate is Köppen Cwb — tropical altitude — hot and humid through the summer, cold and dry through the winter, with winter nights that can fall to a few degrees above freezing. Wildlife here includes species the surrounding agricultural landscape can no longer support. Armadillos work the leaf litter. The southern tamandua, a tree-climbing anteater with a prehensile tail, forages at night. Two threatened cats hold on: the ocelot, spotted and roughly twice the size of a housecat, and the cougar, which needs far more territory than 2,069 hectares can provide and treats the park as one node in a larger range. Seeing either is unlikely. Their tracks in the trail mud are not.