Recommendations for city breaks?

Hi all,

My mate and I are planning to go away for a few days in April. Currently looking for suggestions of any cities in Europe to go to. I've been to a few cities already around Europe and I don't plan to do a repeat- kinda wanna go somewhere new.

Here's where I've been recently (over the last 3 years):

Berlin

Amsterdam

London

Milan

Brussels

Brugges

Athens

Will be flying out from Dublin as well.

Any recommendations would be great that is none of the above.