Mahashasthi, the start day of Durga Puja, starts with 'Devi Bodhan' and integral drum-beats marks the spirit. Drum, known as 'Dhak', enthralls the heart of the millions with its majestic rhythm. Vedic hymns are chanted from early in the morning, to mark Devi Durga's presence on earth. She and her children are ornamented with flowers, garlands and new dresses are wrapped around them, to welcome them on earth. The spirit of Mahashasthi is lighted through all and sundry, who start visiting the local mandaps (pavilions). This is the day, on which we see the idol for the first time, inside local pandels. She is unveiled through vedic rituals, before the worship.
Following 'Bodhan' on Shasthi, Mahasaptami is marked by bathing of Banana tree (Kalabou Snan), in the holy river Ganges. This is when 'Life' is inflicted in the clay idol and 'Anjali' or public worship is started. It marks the auspicious moment when again drum beating is followed in a melody. Kalabou is supposed to be the wife of 'Lord Ganesha', and she is worshipped in a similar way, on the same day. There are facts and fictions, supporting interesting stories, against this incident, as per Hindu mythology. It is said that, 'Lord Ganesh' was afraid to marry, as he thought that there might be a rift between his mother and wife. He thus married a banana tree instead, so that no problems arise. However, Kalabou snan remains and interesting part of the entire puja.
Asthami puja, begins on the next day. The worship reaches the peak during 'Sandhi Puja', the crossover time between Asthami & Navami (an auspicious moment in the Bengali Calendar). This is when pundits chant vedic hymns followed by 'Arati' of Devi Durga using 108 candles (viz. pradeep in Bengali). She is then worshipped with various ingredients, before the 'Navami' puja, which is when animal sacrifices are made in some places, to mark the power of goddess.
Eating delicious dishes is a part of the celebration. Navami is celebrated through savouring meat in most of the Bengali families, while Asthami is marked as a day to observe 'being vegetarian'.
Puja ends with Dashami, when the idol is worshipped by Bengali married ladies for the last time. She is immersed in vermillion and sweets before being physically immersed in the holy river Ganges.
The Durga Puja continues for a period of ten days, although these ten days happen to be the spirit for all the Bengalis throughout the year. Actual worship starts from the sixth day and is restricted to four days only. But Devi paksh starts right from the day of Mahalaya (i.e. when Goddess Durga starts her journey to earth), and the everlasting spirit of Duragapua persists till 'Diwali', when the goddess is worshipped in another form called 'Kali', an embolization of supreme power.
The spirit remains fresh till 'Bijoya Greetings' are over, when each one of the Bengalis exchange good wishes, regards along with the tunes of celebration.