Unsure if this video was shared previously.
It contains some very interesting details from 40’s onwards.
There are more than a few mentions of crashed, and recovered craft in this lecture, along with quotes from senior officials as regards the nature of the craft crashed/recovered.
I think we would all love it if those of us with the skills could hunt down, and present any other detail, including modern “foia” ( or country equivalent ) on the alleged crashes, and subsequent retrievals.
I have tried a bit, but my internets are far weaker than they ought to be.