The Baháʼí Faith has eleven holy days, which are important anniversaries in the history of the religion.
[1] There is no fixed format for any of the holy days, and Baháʼí communities organize their own commemorative meetings.
[2] All but two of the holy days are scheduled annually on fixed dates in the Baháʼí calendar.
The Twin Holy Birthdays are scheduled annually according to a lunar calculation.
See Ascension of ʻAbdu'l-Bahá The Twin Holy Birthdays of the Báb and Baháʼu'lláh are celebrated on the first and second day following the eighth new moon after Naw-Rúz.