A hat as a landing site for a bird of paradise. This extraordinary headdress was worn by wealthy women in the early 19th century, one assumes to draw attention to themselves. Might the preserved exotic bird transfer its beauty to the wearer?

Even under a fabric camouflage, the characteristic shape of the German spiked helmet, or "Pickelhaube," remains unmistakable. It remained a purely military accessory before it was adapted by police and even firefighters. Most often associated with Prussian soldiers whose uniform the helmet belonged to from the middle of the 19th century, the spiked helmet was famously worn by Otto von Bismarck.

This pink handmade hat with cat-like ears, dubbed the pussyhat, was created to be worn by hundreds of thousands of women taking part in the "Women's March" that happened across the US and the world in March 2017 to protest against the misogyny of the newly elected US President, Donald Trump. The hat has since became a feminist trademark in the #MeToo age.

Respirators are also a special type of headgear. Soldiers wore them in the First and Second World Wars to survive poison gas attacks, a new insidious form of warfare that has thankfully since been banned. But these days masks, if not quite respirators, are commonly used by people living in highly polluted cities.

To oppose the ban on teaching students while wearing a headscarf, Fereshta Ludin went to the Federal Constitutional Court in Karlsruhe in 2003 but lost her case. The dispute over the headscarf ban divided Germany. The "Hat's off" exhibition at the Stuttgart House of History in Baden-Württemberg is advocating for more tolerance, no matter what one chooses to wear on their head.

"Hut," the German word for hat, in this idiom derives from the verb hüten (take care of, watch over, herd animals). If someone warns you to be "auf der Hut," you are being told to be watchful, wary and alert. Protection is key in this image — and it's ingrained in the genes of this this highly vigilant, and furry, meerkat.

If a German says a child grew up "gut behütet," it doesn't mean the girl or boy spent their childhood wearing particularly good hats but that they were sheltered and protected. The parents will likely have been "auf der Hut," just like the meerkat in the previous picture.

Not too long ago, in an era when most men would not have left the house without wearing a hat or cap, they would take them off as a sign of respect in church, in the presence of a lady or their bosses. The German expression "Hut ab" is used to show admiration and respect for another person's actions and has its equivalent in English: hats off!

The phrase "Hut nehmen" means to resign, to step down, pack one's bags, grab one's hat — and leave. People may no longer wear hats as a matter of course, but the idiom is still very much in use, in particular after a person has been fired.

This German saying literally translated as "that goes way beyond my hatband" means to go too far. Its origins are not entirely clear. One version has it that the idiom refers to the alleged medieval practice of ensuring that the stream of water spouting from a village well was no thicker than a hatband. Anything else would have been aggravating and going too far.

After a dressing down, you might feel useless and at fault, and maybe two feet tall, or as the Germans say, "so small with a hat on." The phrase is usually accompanied by using thumb and index finger to indicate exactly how insignificant one feels.

A hat is symbolic of power and social status. Nowadays, people who can literally "bring it all together under a hat" are good at mediating and finding a consensus among, for instance, different people and opinions. In Germany, it is common to say that women who juggle a job, children and a household "bring it all under one hat."

"Das kannst du dir an den Hut stecken!" directly translates as, "You can pin that onto your hat." The expression is used when someone can't be bothered or doesn't care about something, like in "stuff it." It refers to the fact that people used to decorate hats with bits and ends that weren't really valuable.