What is Silvesterchlausen? Silversterchlausen is an ancient celebration of New Year’s Eve in Appenzell, Switzerland. St. Sylvester’s Day, called Silvester in Switzerland, is New Year’s Eve. The modern Gregorian calendar places it on December 31st. But, before the 1600s, Switzerland used the old Julian calendar which placed the holiday on January 13th. Silversterchlausen is still observed on the old date from the Julian calendar. In Appenzell, Switzerland, Silvester is celebrated with Silversterchlausen, a procession through town filled with yodeling, bells, and garish costumes.