Churchill's Secret Agents: The New Recruits on Netflix is great

"In this history-steeped reality series, 14 contestants undergo the same rigorous selection process as Britain's top-secret World War II spies."

And speaking of spies:

As well as Baron Robert Baden-Powell’s use of entomological sketches to hide his spying activities, embedding floor plans and sketches of enemy forts inside the bodies of insects. pic.twitter.com/fKzYkcsvJY

— Geoff Manaugh (@bldgblog) July 22, 2018