Piazza Castello, Turin, Italy
Torino's Piazza Castello really goes all out for Christmas. There's a massive cone of spectacularly colored lights that create a Christmas tree on the piazza. There's also a giant Advent calendar and behind each door reveals a scene from the bible. I'm not sure how they open each door because the calendar is so huge; maybe they use a ladder.
On the other end of the piazza is a Christmas market where they sell the craziest cookies and pastries. One had a pile of pastries that were made to look exactly like hamburgers on buns.
My favorite part of the piazza is the people-watching. We must have lingered on the piazza for four or five hours over the course of a couple of days, just watching the people of Tonino do their shopping, grab an espresso, or meet friends on the square.