Capitólio

The canyons here were dry once. Water cut them along conjugate fractures in the white quartzite of the Grupo Araxá, and then the Furnas dam filled the whole system, so the gorges became corridors you can sail into, 20 to 60 metres of rock either side and emerald water underneath. In the narrow stretches the boatmen cut the motor, and what is left is birdsong and water working on stone.

The Serviço Geológico do Brasil catalogues the Cânions de Furnas as a geosite of national relevance on both its educational and its touristic scores, with sedimentary structures and deformation readable straight off the walls from the deck. On 8 January 2022 a quartzite block came away from a canyon wall onto tourist boats and killed ten people, a pilot and nine visitors. The inquiry found no single trigger: the block had lost its footing to erosion at the base, and the expert put on record that hundreds of others in the region stand in a similar condition. What came after is the reason the place works now, a published monitoring cadence with geological assessment fortnightly from April to September and weekly through the October to March rains, the canyons shutting if significant movement is found, and every person aboard a boat registered with the Navy before it leaves. Visitor numbers halved after 2022, the day-trip crowds thinned, and the people who come now stay a week or two and often pair Capitólio with the Serra da Canastra.