There were no locked doors, no guards, no security cameras. There was barely even a doorway.

The small hut outside the ancient cemetery of San Juan, a town just south of the salt plains of Bolivia, contained precious artefacts from centuries-old communities.

It's hard to imagine such a place being so unguarded in New Zealand, but understandable given the archaeological treasures that have been here, unharmed, for 800 years.

Just beyond the hut - and five bolivianos ($1.20) entry, if there's someone there to collect - are dozens of rock structures, some 4m high.

They are tombs, or chullpas, covering a 4ha region and open to the sky so the occupants - dusty, faded skeletons - can star-gaze if it pleases them.

It's an eerie feeling, intrusive even, to poke your head into a gap in a mound of rock and find a full skeleton as if it had been placed there only yesterday.

In accordance with the customs at the time, the corpses had been placed in an upright, seated position, their knees to their chests, wearing their best clothes.

Alongside the bodies are tools, bowls of long-gone food, ceramic vases - anything that symbolised their lives or could be useful in the after-life.

The tombs were built according to their eternal occupant; those of higher status were placed in taller, grander chullpas. Some had families in them, with small skeletons of children sitting side-by-side.

Most artefacts that had escaped the after-life ended up in the local museum, or the hut near the entrance: old hoes - shafts of wood with a rock tied on the end - ceramics, leather moccasins, stone tools, even plaits of hair. And not a single cabinet to obstruct our gaze or touch.

Staring at the tombs from the opposite side of San Juan are fertile slopes, still with rock fences separating crop-zones. According to the museum pamphlet, a community of hundreds lived here from 1200 to the late 1500s, growing quinoa and storing crops in deposits on the hillside. The workers were split into groups; the crop-growers, the llama farmers, the hunters, the transporters.

They used stone tools and, after the Incas arrived from the north, spoke the Quechua language. They used copper and bronze objects and shells from the sea. The hunters killed vicuna, a deer-like creature, for meat as well as for wool to make clothing.

As with other tribes all over South America, they worshipped the sun and the land - which provided the means for food - and offered them sacrifices and held ceremonies in their honour during which they drank chicha, a fermented drink from maize or quinoa. Among the 300 items at the museum is one such offering - a mummy of a man 164cm-tall.

The pamphlet concludes: "[But] they lived with a tremendous disadvantage ... in a territory of marked aridity and lacking water, two facts of nature that applied the brakes to their human development."

We left with the feeling of having flipped through the pages of history.