Where does this come from, and can I check it?

Crop marks and shadows in low sunlight revealed ditches under farmland. The figure is taken from Historic England, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a history fact?

Yes. It sits on the History shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Aerial photography exposed fields nobody had noticed

Crop marks and shadows in low sunlight revealed ditches under farmland In the years after the First World War, pilots noticed that buried walls and ditches show up from the air as differences in crop height and soil colour. The archaeologist Osbert Crawford and others built up systematic photographic surveys of Britain. Thousands of prehistoric and Roman sites are known only from such photographs. It sits in Mondo's history collection, one of 200 facts that each trace back to the reference below.

Where this comes from

Historic England

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Tags: aerial-survey, archaeology, landscape

Aerial photography exposed fields nobody had noticed: the short answers

Where does this come from, and can I check it?: Crop marks and shadows in low sunlight revealed ditches under farmland. The figure is taken from Historic England, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a history fact?: Yes. It sits on the History shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.