This is amazing. Spotted these walls half way up a vertical cliff in the Tajos de Bermejales. Who built them and why?
From Wikipedia ...
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Neolithic people lived in the canyon 5,000 years ago, sheltering under its overhanging walls and using the river as source of food. There are traces of these early settlers on the canyon walls about 10 metres above the present river level. Some of the walls they built to enclose the cavities in the canyon wall are still visible.
