Anyone aware of the yt chan of the man who used a musical performance as cover to covertly ultrasound a very important religious artifact? It was a tomb or box, about 5 feet long if I remember correctly. He (and his assistant?) did it standing/performing at the altar of one of the most famous churches on the planet, if full view of the audience watching the performance he arranged.

This same person made a intensely interesting video about the cover of a book from a famous artist, and convincingly demonstrated the artist knew either the meter, the cubit, or the speed of light (my memory) long before they were introduced to the public.

I lost the link. I almost certainly have the whole channel archived, but so far have been unable to locate it.