Answer:
The names of some anniversaries provide guidance for appropriate or traditional gifts for the spouses to give each other; if there is a party these can be brought by the guests or influence the theme or decoration. These gifts vary in different countries, but some years have well-established connections now common to most nations: 5th Wooden, 10th Tin, 15th Crystal, 20th China, 25th Silver, 30th Pearl, 40th Ruby, 50th Golden, 60th Diamond.