Super cool approach to combating counterfeit bank notes, via Quartz.

The European Central Bank (ECB) has been particularly keen to redesign the yellow-orange bill that is its most popular denomination, accounting for nearly half of all banknotes in circulation—and is also among the world’s most counterfeited notes.

Like the €5, €10, and €20 notes in the Europa design series, the surface of the new €50 note features a collage of symbolic architectural motifs drawn by German postage-stamp designer Reinhold Gerstetter. Aside from the usual layers of security features—watermarks, color-changing inks, threads, and microprinting—Gerstetter’s design also features a “portrait window” that frames a hologram of Europa, a Phoenician princess in Greek mythology for whom the continent is named. The princess also appears as a watermark when the banknote is held up to the light.

The idea for using a face as an anti-counterfeiting device came from neuroscientists.

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