Kalambo Falls
Nature publishes the Kalambo Falls interlocking-log discovery
View full image ↗ How was this image made?
The creative brief sent to the image model. These are instructions, not a record of what actually happened.
Original prompt & settings (JSON) ↗The upper log is 141.3 centimetres long, and its hand-cut U-shaped notch still fits over another trunk after nearly half a million years.
A publication day, not a dig day
What happened on 20 September 2023 was the appearance of a peer-reviewed Nature study reporting deliberately worked wood from waterlogged deposits at Kalambo Falls, Zambia, and a public announcement of the results by the University of Liverpool.
The excavation that produced the objects had taken place in 2019, under the Deep Roots of Humanity project led by Larry Barham.
Between dig and paper came microscopic identification of chopping and scraping marks, experimental comparison with stone-tool woodworking, and luminescence dating of the enclosing sediments by Geoff Duller's team at Aberystwyth.
Two logs and a notch
The principal find is a pair of logs joined transversely: a U-shaped notch, 13.2 cm long by 11.4 cm wide, cut into the upper log and fitted over an underlying tree trunk.
They cross at approximately 75 degrees — a skewed joint, not the neat right angle that summaries tend to show.
Luminescence dating of the surrounding deposits gave an age of at least 476,000 ± 23,000 years.
Oldest structure, not oldest worked wood
The claim the paper supports is the earliest known structural use of wood — not the earliest worked wood of any kind. The same paper discusses a polished-plank fragment from Israel more than 780,000 years old.
Only part of the construction survives. Platform, walkway and dwelling foundation are possibilities the authors raise, not identified functions, and no hominin remains lay close enough to name the builders' species.
The evidence supports deliberate structural woodworking and technical cognition; it does not establish symbolic behaviour or a particular social system.
Sources
Researched 24 Aug 2026 4 sources not yet audited
How this was checked
Researched from the web into a fact sheet and rewritten from that sheet. This article has not yet had an independent model audit. How the pipeline works →
What the sources leave uncertain
- The reported age is a luminescence estimate for the deposits surrounding the wood, expressed as 476,000 ± 23,000 years.
- Only part of the construction survives. Platform, walkway and dwelling foundation are possibilities proposed by the authors, not identified functions.
- No hominin remains were associated closely enough with the logs to identify the builders' species.
- “Oldest known” describes the current archaeological record and could change with later discoveries.