Getting to the top generally means four-wheel drive and a slow climb. Then the ground levels out, which is the surprise, because everything about the approach is vertical. The Serra Dourada is a hog back - a sequence of tilted rock beds eroded into a ridge that runs roughly 56 kilometres across otherwise open country, topping out near 1,080 metres. Weather has cut the exposed quartzite into blocks, corridors and freestanding towers, and Brazilians call the result a cidade de pedra, a stone city. The comparison is not much of a stretch; the formations really do line up like streets. Between them grows cerrado rupestre, the rocky-ground version of Brazil's central savanna: low, tough, and far more diverse than it looks to anyone driving past. On the slopes below, semideciduous forest, gallery forest, buritizal palm stands and open campo limpo take over in bands.

The serra is a divide, and that is its real job. Rain soaks into fractured quartzite at the top and re-emerges downslope as springs - thousands of them, by the state's count - which gather into the Uru and the Fartura and run north into the Tocantins basin. Cerrado uplands like this one function as water towers for a large part of central Brazil, storing wet-season rain in rock and releasing it slowly through the seven dry months. It is the least photogenic argument for protecting the place and easily the strongest. Burn or clear the top and the springs below do not simply run dirtier. Over enough years, some of them stop.

The Goiás state government created the Parque Estadual da Serra Dourada by decree on 5 June 2003, drawing a line around some 28,600 hectares - close to 30,000 by the state's current figure - across three municipalities: Mossâmedes, Buriti de Goiás, and Cidade de Goiás. Inside that line sat 188 separate private properties, every one of which would eventually have to be bought, swapped or expropriated. Then very little happened. A 2008 thesis on sustainable ecotourism in the park found that nothing at all had followed the decree: no management plan, no environmental education for visitors, no infrastructure, and an enormous amount of unrealised potential going nowhere.

In June 2014 the state environment secretariat took up a proposal from the rural producers' union of Cidade de Goiás to shrink the park. A consultant for the Federation of Agriculture and Livestock of Goiás put the case bluntly: the park “exists only on paper, was created without the studies required by the legislation, and to this day no one knows where it begins and where it ends.” The vice-president of the Goiás branch of the Association of Brazilian Geographers replied that the proposal made no sense at a moment when the effort everywhere was to save what remained of the cerrado and recover what had already been lost. Both sides were describing the same failure from opposite ends. Land regularisation is still grinding through the courts. Public access, meanwhile, is limited to the biological reserve the Federal University of Goiás maintains at the summit, by prior authorisation, and the most fully developed planning document the park possesses is a strategy for managing fire.

Mossâmedes is the usual way in, about 40 kilometres from the park and roughly 150 from Goiânia. The third municipality on the map is more famous. Cidade de Goiás is the colonial capital that Goiás abandoned in the 1930s in favour of a brand-new city on the plateau - a grid of stucco facades and pebbled streets that UNESCO inscribed as World Heritage in 2001. Claude Lévi-Strauss passed through in 1937, found the quays caving in under lianas and banana trees, and thought the dilapidation added dignity rather than subtracting it. The serra stands behind the town, the same ridge it has always stood behind. From the top on a clear morning the plateau falls away in every direction, and the argument over where the boundary line should run looks very small indeed.