Euros

As always, if your bank does not charge you a Foreign Transaction Fee (FTF) and/or an "Out of Network" fee, then using an ATM is almost always the cheapest. You get about a 1% bump over the exchange rate you see on the internet as the "Interbank" rate. You may also pay a use fee at the ATM, a few euro.

Getting euros here is at best about a 5% premium, typically 7%. Exchanging physical cash is about the worst way to do it, probably in the range of 7-10%, possibly more.

Edit: Should add, you will use mostly a credit card though, not much need for lots of cash.

Just use credit cards.