This was a 16th century mask designed for women. Worn during travel, it was designed to protect from sun exposure (pale skin was seen as fashionable amongst the wealthy women in society). Covered in black velvet, the mask was sometimes held in place by chomping down on a mouth piece, effectively silencing the wearer (supposedly to make them appear more “mysterious” in their silence).
Plague Doctor's Mask
Though plague doctors existed since at least the 6th century, the mask and associated costume only came about in the 17th century. The beak is roughly a foot-and-a-half long and is filled with fragrances. At the time it was believed that bad smells transferred diseases.
Brewster Body Shield
The complete package—the massive helmet and all-encompassing body armor—were designed by the United States army during World War I. While effective at withstanding gunfire, the original design was difficult to maneuver and weighed forty pounds. The final version was cut down to a slim and trim eleven pounds.
E1R1 Dog Gas Mask
An experimental gas mask for canines. Though this particular design was more of an experiment/proof of concept, dog gas masks were introduced (by the US army, anyway) during World War I before becoming more common amongst more countries in World War II.
The Mask of Infamy
This was a torture device, though the mask itself didn't inflict any physical pain. The victim was forced to wear it as humiliation while chained to one spot to be tortured by those nearby. Sometimes a ball was placed in the mouth to prevent the wearer from screaming (apparently a common trait amongst creepy headgear).