Content of: Picture of the Day 11/20/25 - Wikimedia Commons
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11/20/25 at 07:16AM
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Photography
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Geological fieldworks, underground in the Estonian oil shale mine to study the variable mineralogical and chemical composition and microstructure in the different layers of the oil shale profile.
Peeter paaver, CC BY 4.0, via Wikimedia Commons. View source.
