We live in the UK and are hoping to take a three-day-long-ish city break next Spring, some time around May but quite possibly later. I've looked into quite a few cities already but everywhere's so attractive and so different it's really hard to come to a decision. Just as a few details:

• We're not interested in going to the UK, Switzerland, Paris or Berlin as they're places we either live in (UK) or have been to before.

• Regarding climate, somewhere with mild temperatures would be nice, so basically anything that's not ridiculously cold or ridiculously hot.

• Points of interest include things like architecture, culture, history and food (I don't mean to sound pretentious at all, so sorry if any of that comes off as such). Mountainous areas, particularly the Alps, are somewhere we all really enjoy going to so any city in that area with access to Alpine activities (e.g. hiking) would be good to look into.

Places we're quite interested in are Prague, Amsterdam, Vienna and Lisbon, but really any suggestions are welcome. I've looked into a few smaller cities like Ljubljana, Bruges and Salzburg, but we're a little concerned about there not being enough to fill three days in those places so any advice on that would be greatly appreciated.

Edit: I should have worded it differently but when I mentioned the hiking my thoughts were more that it'd be ideal for a city to fill three days, but if it were somewhere that could only fill one or two days but would still be worth going to we'd be happy to do something like hiking to fill the spare time. It's not really something we're specifically looking for a city to offer though.