The Festival of Ridvan, termed by Baha'u'llah, the "Most Great Festival" and the "King of Festivals", commemorates the twelve days that Baha'u'llah spent in the garden of Ridvan outside Bagdad. The festival commemorates Baha'u'llah's public declaration of His mission to His family and closest followers. The first, the ninth, and the twelfth days of Ridvan are Baha'i Holy Days on which work is suspended.
Description provided by Multifaith Calendar