The Harbin (China) Ice Festival
This is probably the most spectacular ice and snow carving and building festival in the world. Although I have not yet visited it, due to not really having the time these days, I do hope one day to see it in person. Click the link to see some of the most fantastic ice creations you will ever see. They are most effective when lit up at night, as you can see:
http://edition.cnn.com/2014/01/03/travel/harbin-ice-festival-2014/index.html
As well snow sculptors come from all over the world to create these magnificent snow scultures - click the link to see them:
http://www.visualnews.com/2013/12/26/harbin-ice-festival-2014-unveils-snow-sculptures-early/