In the main square in Zagreb, Croatia, you can find this building:
And if you walk up to that arch, you’ll see this plaque.
Walk down the alley in the arch and you’ll find Peroklinika, a small fountain pen shop and repair store owned by Vlasta Keranović. You can read about the store and Vlasta in this article.
Vlasta sells a reproduction of the world’s first mechanical pencil, and I couldn’t resist buying one for myself – a perfect souvenir of Zagreb!
For more information about the original Penkala brand, this site is a good place to start.