Riḍván is a twelve-day festival in the Baháʼí Faith, commemorating Baháʼu’lláh’s declaration that he was a Manifestation of God. In the Baháʼí calendar, it begins at sunset on the 13th of Jalál, which translates to the 20th or 21st of April, depending on the date of the March equinox (exactly one month on the Gregorian calendar after the equinox). On the first, ninth and twelfth days of Ridván, work and school should be suspended.
“Ridván” means paradise, and is named for the Garden of Ridván outside Baghdad, where Baháʼu’lláh stayed for twelve days after the Ottoman Empire exiled him from the city and before commencing his journey to Constantinople.
It is the holiest Baháʼí festival, and is also referred to as the “Most Great Festival” and the “King of Festivals”.