Here in Germany (sorry I start most of my posts with this but I like to make it clear as it often affects what I'm going to say), many foods are unknown or only available with difficulty.
For example my DH's aunt told of when they first saw tomatoes. Tomatoes are included in Mrs Beetons cookbook so were certainly known in the UK before said aunt was born.
When I arrived here in the 70s I got to know lots of things that were new to me but were standard in myother in law's cuisine: lamb's lettuce, celeriac, quark, buttermilk, and cake for breakfast on a Sunday being among them. So sometimes things that are everyday to some are unusual for others.
I have eaten snails, oysters, eel, brain, and lots of the things mentioned above, except tripe.
The only thing I would never touch, although I have eaten it in my childhood is
Beetroot!
My mother never served up a salad without one, but I soon learnt to refuse - I shudder at the thought of it!