It's heaven for science nerds.
Armillary spheres (including a room sized one from the 1500s), all manner of astrolabes, astronomical clocks, hand ground lenses and microscopes and telescopes and Galileo's actual middle finger (https://en.wikipedia.org/wiki/Galileo's_middle_finger), a tabula affinitatum, michelangelo's compasses, even an organum mathematicum!!!!! (https://en.wikipedia.org/wiki/Organum_Mathematicum)
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The Germans tried graphite, but of insufficient purity[1], and concluded heavy water was the only way to go. They "didn't have enough of" that because of allied sabotage efforts[2]. There were some pretty thrilling heroics on display here that would make for a fantastic movie (or historical novel ;) ).
Even had both of these things gone Germany's way in some alternative history, they would still have faced an immense challenge in scaling up their operation under wartime constraints. The scale of the Manhattan project's enrichment efforts was truly colossal.
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[1]https://link.springer.com/article/10.1140/epjh/s13129-025-00...
[2]https://en.wikipedia.org/wiki/Norwegian_heavy_water_sabotage
One day I hope to find a late 1800s automatic groundwater datalogger. Think of a seismometer that sits on top of a groundwater well to measure water levels. It would be a dream find for me.