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

Each of its two main spans measures 521 metres, carried on steel tubes up to 4 metres in diameter. The figure is taken from UNESCO World Heritage Centre, 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 technology fact?

Yes. It sits on the Technology 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.

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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

The Forth Bridge is a pair of giant cantilevers

Each of its two main spans measures 521 metres, carried on steel tubes up to 4 metres in diameter The bridge opened in 1890 and used about 53,000 tonnes of steel, a material then still new to large structures. Its three towers stand on caissons, and the arms reach out to meet at mid span, so the bridge resists wind and load without cables. Trains still cross it, and it was inscribed as a World Heritage Site in 2015. It sits in Mondo's technology collection, one of 200 facts that each trace back to the reference below.

Where this comes from

UNESCO World Heritage Centre

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: bridges, steel, railways

The Forth Bridge is a pair of giant cantilevers: the short answers

Where does this come from, and can I check it?: Each of its two main spans measures 521 metres, carried on steel tubes up to 4 metres in diameter. The figure is taken from UNESCO World Heritage Centre, 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 technology fact?: Yes. It sits on the Technology 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.