Cork is amazing. It is a natural substance that comes from the bark of a tree. Though it looks porous, it is actually impermeable. It doesn’t absorb liquid. (Well, very little.) Cork is also buoyant, meaning it floats. And elastic. And fire resistant. All of which is why, for hundreds of years, it has been made into “corks” to be used as stoppers in wine bottles.
There’s a part of Portugal that produces half of all the cork that is harvested worldwide. Here is a short video about that…