1. Zagreb
When temperatures drop (and they really do drop, often to freezing and below) the city loses none of its charm - the cobbled streets of the old town and the stately lawns by the train station, when they're covered in snow, look like they were dreamed up for a confectioner's shop window.
But one of the nice things about a winter break in Zagreb is that so much of its joy is found indoors. November's film festival kicks off a season packed with culture, be it in the form of music or museums. Come in January, and you can have a surreal midnight strolling through a gallery on Museum's Night.
Uniquely, a city break in Zagreb can double up as a skiing holiday. Mountain Medvednica is just a twenty minute drive from the city, and its Sjleme ski resort is never overcrowded.