Answer: Feudal Japan

If you’ve ever wandered through the Arms and Armor section of a museum, even if you don’t recall most of the armor you saw, you likely recall the distinctive look of the Japanese mempo. Unlike other armor styles that hid the wearer’s face behind a smooth and cool sheen of steel, the mempo hid the wearer’s face behind, well, another more terrifying face.

The defining characteristic of the mempo, especially the widely recognized somen and menpō styles that covered the whole face and the lower face respectively, is that the facial armor was designed to look like a more terrifying version of a human face–at times complete with facial hair.

In addition to terrifying their enemies and protecting their faces, the mempo also served a very practical purpose: they balanced out the weight of the top heavy kabuto (the actual helmet portion of the head armor) and helped secure the chin cord (shinobi-no-o) of the kabuto to keep the helmet positioned firmly and safely atop the wearer’s head.