Isn't it cool that a hundred years after the introduction of the German 1915 Stahlhelm, almost every country's military is using a variant?

Today's helmets are not the same as the 1916 helmet (there was no 1915 variant), although some share the neck-protective feature on the back, superficially making them appear similar.

American helmets have a bulge above and around the ears and the bill is more visor-like.

British Mk. 7 helmets currently in use dispense with the bill entirely. The neck "sweep out" is also eliminated, so the deepest part of the helmet is actually around the ears.

The point being what exactly ? A helmet is not designed nor intended to be "cool".