Rabi al-Awwal 08 is the martyrdom (shahadat) of Imam Hassan al-Askari (11th Imam) AS AND the beginning of the Minor Occultation of Imam Muhammad al-Mahdi, peace be upon him and may Allah (سُبْحَانَهُ وَ تَعَالَى) hasten his return. https://www.al-islam.org/sw/node/14886
Condolences. In the US and Canada. Please consult your local authorities in other countries for Islamic holy days.