Pickelhaube
The pickelhaube (German Pickel, "point" + Haube, "helmet") is a spiked helmet worn in the 19th century by German military forces.
The pickelhaube was originally designed in 1842 by King Frederick-Willliam IV of Prussia. and its use slowly spread to other German principalities. In 1887, the Kingdom of Bavaria was the last German state to adopt the pickelhaube, but by then it was already going out of fashion, and by the time of World War I it was reduced to ceremonial wear. With the collapse of the German Empire in 1918, the pickelhaube was abandoned and replaced by the "coal shuttle" type of helmet that would still be worn by German troops in World War II.
