Many Christian communities, particularly the Catholics observe the Feast of the Immaculate Conception on December 8.
It is a holy day which celebrates the solemn belief in the Immaculate Conception of the Blessed Virgin Mary and is celebrated nine months before the feast of the Nativity of Mary, which is celebrated on September 8.
Celebrations of Feast of the Immaculate Conception 2017 :
It is one of the most important Marian feasts celebrated in the liturgical calendar of the Roman Catholic Church.
The day is often celebrated with Holy Mass, parades, fireworks, processions, ethnic foods, and cultural festivities in honor of the Blessed Virgin Mary.
By Pontifical designation and decree, it is the patronal feast day of Argentina, Brazil, Korea, Nicaragua, Paraguay, Philippines, Spain, the United States and Uruguay. By royal decree, it is also designated by as the Patroness of Portugal.
The Feast of the Immaculate Conception is a public holiday in countries like East Timor. Guam, Italy, Malta, Monaco, Spain, etc.
Apart from that there are many regions in Australia, Canada, United Kingdom, and United States which have a holiday on this day.