The Peace Clock in Hiroshima, the top counter is the number of days since the bombing of the city, and the lower counter is the number of days since the latest known nuclear detonation.
I wouldn’t call the US tests “clandestine”. They’re subcritical, meaning they don’t generate any nuclear yield. They also report when they do these in the annual NNSA reports.
Interesting, they were “sub critical” tests. I mean that really shouldn’t count…puts them on par with actual detonations (which Russia is clearly prepping to do soon with tactical nukes).
Why shouldn't they count? It's literally testing a nuclear weapon. The clock does not say: "Time since the last detonation of a nuclear weapon".
Edit: But one could argue that nuclear weapons get tested all the time without any kind of detonation. These should count too IMHO.
Edit: just read another article on the tests. They happen to design new weapons with them which makes them not tests to see if the nukes still work like I thought.