Incahuasi Island

Where it sits. Isla Incahuasi is a rocky outcrop standing roughly in the middle of the Salar de Uyuni, in Potosí Department in south-western Bolivia, about 80 kilometres west of the salt-processing village of Colchani and some 100 kilometres from the town of Uyuni. It covers about 25 hectares and rises around 40 metres above the surrounding salt crust, which is at 3,656 metres above sea level. From the summit path the flat runs to the horizon in every direction with no feature to interrupt it except the volcanic cone of Tunupa away to the north — the one place on the salar where the eye gets both the scale of the plain and something to measure it against. The Quechua name means "house of the Inca"; it is often confused with Isla del Pescado, a separate and larger island a few kilometres further north.

The story behind it. The island is the eroded remnant of an ancient volcano that stood in the basin when it held water. During the high stands of the prehistoric lakes — Lake Minchín and later Lake Tauca, which filled this basin until roughly 15,000 years ago — the outcrop was a genuine island in a genuine lake, and its lower slopes are encrusted with the proof: fossilised algal and coral-like deposits, formed by organisms that grew in the shallows around a shoreline that has since evaporated. Walking up the path, the sequence is legible in the rock. Small stone structures and offerings on the island indicate pre-Columbian use, and the salar was crossed for centuries by llama caravans carrying salt and produce between the Altiplano and the valleys, for which islands like this served as waypoints and overnight stops.

The cacti. What covers the island is a dense stand of Echinopsis atacamensis, the giant columnar cactus of the high Andes, some individuals exceeding ten metres. Growth is slow at this altitude and in this aridity — on the order of a centimetre a year — which makes the largest specimens close to a thousand years old, and makes the casual damage done by visitors leaning on them a serious matter. The plants survive on almost no rainfall, drawing on fog and the small amount of moisture the porous volcanic rock holds. Viscachas, the long-tailed rodents that resemble rabbits, live in the rock crevices and are commonly seen in the early morning; a few small bird species work the flowers when the cacti bloom.

On screen. The island's role is as the anchor of the salar's screen identity rather than as a set in its own right. Star Wars: The Last Jedi (2017) built the planet Crait — the white mineral world where the film's final battle is fought — from photography, textures and reference gathered on the Salar de Uyuni, while the live-action ski-speeder sequence was staged in England; the flat that appears behind Crait's red streaks is the same crust that surrounds Incahuasi. Werner Herzog's Salt and Fire (2016) shot on the salar directly, using the island and the plain around it, and documentary crews return to Incahuasi constantly because it is the only vantage point that lets a camera show what a salt flat of 10,580 square kilometres actually looks like from above its surface. Most standard Uyuni day tours stop here for exactly that reason.

What you actually see today. A small entrance fee is collected at the base. A marked loop trail climbs through the cacti to the top in about twenty to thirty minutes, over sharp fossil rock that demands proper shoes, with a viewing point at the summit and interpretive signs on the geology. A basic café, toilets and a shelter operate at the foot of the island, and tour groups typically stop for lunch here before driving on. Numbers are concentrated between roughly eleven and two, when the day trips converge; arriving outside that window changes the experience entirely. Nothing about the terrain is wheelchair-accessible, and the altitude makes even a short climb harder than it looks.

Getting there and timing. The island can only be reached by vehicle across the salt crust, on a route that guides read from the polygon patterns and horizon bearings rather than from any road, so it is only visited on an organised tour from Uyuni — roughly two hours each way. Access depends on the season. From May to November the crust is dry and hard and vehicles cross freely; from December to April, standing water turns the flat into a mirror, which is spectacular for photography but can put the island out of reach for weeks when the water is deep, since salt water destroys vehicle underbodies and operators refuse the crossing. Nights are far below freezing in the dry season, the wind is constant, and the ultraviolet at this altitude over a white reflective surface is extreme — a hat, sunglasses and heavy sunscreen matter more here than warm clothing.