Fans are so much more than fashionable accessories: They are useful for flirting, can cool heated cheeks or hide an unladylike emotion. In the wake of the Napoleonic War, their usefulness was boosted beyond the known limit when fans were made for spying, i.e. discretely observing the surrounding or other persons. I found some examples of these extraordinary devices when I visited the exhibition “Waterloo: Life & Times” of the Fan Museum in Greenwich, UK.
