Genootschap

The formal calendar — garden shows, regattas, balls, opening nights and civic ceremonies — is the oldest layer of the season and the most public: Chelsea's flower show and Henley's regatta in the English summer, Trooping the Colour in June, the Vienna Opera Ball on the last Thursday before Lent, La Scala's opening on the 7th of December, the Metropolitan Opera's in September, Le Bal des Débutantes in Paris at the end of November. New Year's Eve in St. Barts and in Sydney are listed here because they are the two nights the yacht world and the southern summer converge on a single harbour.

Most of these sell tickets to the public; the balls sell them in tiers; the ceremonies are free to watch from the street.