[ghotli]

I've been to that museum and was most struck by the small section about Einstein informing the president at the time that the math meant nukes were possible and likely would exist in the short term. There's a lot of cool stuff in that museum, but that's the one that stuck with me. It's written with a typewriter and signed by Einstein, iirc.

[boomboomsubban]

It's rather famous. Written by Leo Szilard but signed by Einstein who later seemed to regret it. https://en.wikipedia.org/wiki/Einstein%E2%80%93Szilard_lette...

I don't understand why it would be in the Spy Museum.

[Uhhrrr]

Cold War relevance, maybe?

[Yoric]

As far as I remember, this letter started the race to nuclear weapons between the US and Nazi Germany. Lots of spycraft involved in that race.