I went to Berlin when the wall was up 40 years ago and revisited the city last year for the Christmas markets. The change was astounding and quite surreal. It is a thriving and lively city with so many activities to choose from. I found the easiest way to get around was on the hopper buses, there are two different routes to choose from which, between them take in most of the city. Trying to speak the language was much appreciated by the locals who immediately switched to English. The markets were magical, especially Charlottenburg but there are so many to choose from. Plenty of history to learn and lots of walking tours on offer for the more energetic. Highly recommend it as a destination.