The trick is a matter of proportion. The stream feeding the falls is modest, the drop enormous, and the gap between the two gives the wind more than enough time and distance to dismantle a column of water into mist. The rim sits at roughly 1,280 metres, high on the escarpment of the Chapada Diamantina, and the air moving up the cliff face rarely rests. In the wet months the flow thickens and something recognisable as a waterfall makes it partway down. In the dry season the whole thing can vanish, leaving a wet stain on the rock and a smell of damp stone. For decades Cachoeira da Fumaça was called Brazil's tallest waterfall, a title since contested by a taller drop measured in the state of Amazonas. What has never been in dispute is that it is the strangest.

There are two ways to meet it, and they produce completely different memories. From above, the walk is about six kilometres from the ecological base in the Vale do Capão, a steady climb onto the plateau that ends with no warning at all: scrub, rock, and then nothing under your boots. From below, the approach is a trek of roughly three days out of Lençóis, the old diamond town that serves as the region's front door, walking up through valleys toward the base of the cliff to look at the fall the way it was meant to be seen. Neither route is a stroll. The plateau above the falls is featureless enough that hikers do get lost on it, and guides are the local norm rather than an upsell.

People in the valleys below had always known the waterfall was there. What changed in 1960 was who else found out. A bush pilot named George Glass spotted the drop from the air and told the wider world, and the falls picked up a second name it has never quite shed: Cachoeira do Glass, Glass Falls. It is a small, familiar pattern. A landmark that had been part of daily geography for generations acquires the surname of the outsider who reported it, and both names go on living side by side. Ask in Vale do Capão and you will hear Fumaça. Read an older map and you may well find Glass.

The falls sit inside the Chapada Diamantina, the Diamond Highlands, a landscape that was ransacked before it was protected. Lençóis was founded in 1844 after alluvial diamonds turned up in its streams, and the mining that followed was brutal work done largely by enslaved people and, later, by labourers who lived badly for a share of whatever they could wash out of the gravel. The stones thinned, the rush ended, and the region went quiet for most of a century. In 1985 the Chapada Diamantina National Park was created over some 1,500 square kilometres of table mountains, canyons, caves and waterfalls, Fumaça among them. The prospectors have been replaced by hikers, which is a better fate than most goldfield landscapes get.

One more constituency knows this cliff intimately, and it is not Brazilian. In the 2006 Hindi film Dhoom 2, Aishwarya Rai's character Sunehri is dared to leap from the edge with no safety line to prove herself to Hrithik Roshan's Aryan. She jumps. He follows her over, bungee cord in hand. The scene put the Smoke Falls in front of an audience that will likely never hike the Vale do Capão trail, and it means a certain share of the visitors standing at the rim today are not there for the geology at all. They are there because they watched somebody jump.