Puma Punku's precise stones

The claim

"The H-shaped blocks are cut so precisely they must have been machined."

Where the idea comes from

A favourite of "Ancient Aliens", which highlighted the repeated, interchangeable H-blocks and smooth faces.

What the evidence shows

1. The stones are red sandstone and grey andesite, both workable with harder hammerstones, sand and water as an abrasive, and grinding. Tool marks and unfinished pieces remain.
2. Identical H-blocks point to the use of templates, a technique also found in Inca and Egyptian work.
3. The blocks were held with I-shaped metal cramps. Analysis shows some were poured molten into the cut sockets on site, using a portable smelting technique.
4. The site was never finished, was damaged by earthquakes, and was quarried for building stone for centuries, which is why it looks like a scattered puzzle.

What is still open

Some details of the masonry techniques and the building's original layout are still being reconstructed.

Our verdict

Explained Skilled stonemasons with templates and abrasives, not machine tools.

Sources

• Tiwanaku (UNESCO)
• Pumapunku (Wikipedia)

Checked 31 October 2026. Spotted a newer source? Tell us.