It's a neat subject. It was built to house The Great Exhibition of 1851.
The wiki page on it talks about the toilets.
The first modern pay toilets were installed, with 827,280 visitors paying the 1 penny fee to use them. The toilets remained even after the exhibition was dismantled. "Spending a penny" became a euphemism for using a toilet.
It's a neat subject. It was built to house [The Great Exhibition of 1851.](https://www.thoughtco.com/britains-great-exhibition-of-1851-1773797)
The [wiki page](https://en.wikipedia.org/wiki/The_Great_Exhibition) on it talks about the toilets.
>The first modern pay toilets were installed, with 827,280 visitors paying the 1 penny fee to use them. The toilets remained even after the exhibition was dismantled. "Spending a penny" became a euphemism for using a toilet.
Cool!