The absolute bestest reason to stay in the EUWatch
There are many anti-counterfeiting measures that are taken when printing banknotes, no doubt maybe the most important part of the process.
One popular method is to use a fluorescent dye that can be detected under UV light. There are many compounds that can be used for such initiatives.
However, the remarkable thing about the the Euro banknote is that element used for fluorescence is ... Europium (Eu).
Some humorous bureaucrat thought it would be hilarious to link such a coincidence (or was it fate) together, and when they have bureaucrat such as them, why leave?
It's the little things in life.