The city has 2 main Christmas markets and you can visit both of them in one day. You can hang around for the main tree to be lit up on Old Town Square and then walk to Wenceslas Square (as in Old King Wenceslas). They are about 5 minutes’ walk from each other.
Beautiful architecture surrounding the square and the wonderful cathedral with its astronomical clock. It was a truly stunning place to visit.
Trdelník is my favorite thing to eat in Prague. The dough itself isn’t actually all that sweet, but the outside has a caramelized richness and aromas of burnt sugar. Perfect with hot chocolate or mulled wine. It's one of the reasons you have to come back to Prague again!
If you are looking for great holiday destinations with beautiful Christmas markets to soak in the festive mood, you have to visit the Prague Old Town Square in December. Very crowded in Christmas season but also very beautiful at night.