The Advent market of Hellbrunn Palace — just outside of Salzburg, Austria — is open from late November until Christmas Eve. Unfortunately, our guided city tour, which included a 15-minute stop at the palace grounds (otherwise closed during the winter) was on Christmas Day.
However, the absence of any other people among the remaining structures and decorations made it easy to appreciate the lesson of a simple good idea plus repetition.
The market areas in the two entry courtyards of the Baroque palace were set within “forests” of 400 cut trees and 13,000 red balls, according to one website.
The palace was (caused to be) built by the Prince-Archbishop of Salzburg, Markus Sittikus, between 1612 and 1615. Its 148-acre park includes a section of trick fountains and a pavilion built for the filming of The Sound of Music.
The Prince-Archbishop used the estate as a pleasure retreat during the long summer days, always returning to Salzburg for the night.
I hope, wherever you are today, that you are enjoying a wonderful holiday season!
Travel tips
Lovely, compact Salzburg makes a good Christmas travel destination, as long as you realize that almost everything will shut down at about 1:00 or 2:00 p.m. on Christmas Eve and not reopen again until December 27. Do your shopping, as well as visit the fortress and other museums, on the 23rd. The two Mozart homes are open on Christmas Day and the 26th, and the guided tour companies are running on those days as well.
Be sure to make dinner reservations for the 24th, 25th, and 26th well in advance (a few weeks out). Our hotel had two good restaurants, and they were so fully booked for Christmas Eve that the hotel was not providing room service that night.
However — this year, at least — the big Advent/Christmas market in the old city center was open through December 26 (although it closed early on the 24th), so it was easy to get a lunch or an early dinner of sausage and gluhwein.
Also, Austria is one of the very few European countries that still allow smoking in restaurants and bars. Ask about it when booking or look around for ashtrays on the tables before sitting down if you want to avoid that sort of nostalgic experience. (Two of our three dinners were in restaurants without smoking.)
enclos*ure 
You are right about the simplicity of the decorations. The red balls look like apples in the bare tree
The Christmas trees here in Germany/Austria are so beautifully shaped, too, with lots of open space between the branches, so the ornaments hang properly.