Maha Shivratri is a Hindu festival celebrated every year in reverence of Lord Shiva.It is also known as padmarajarathri.
Alternate common names/spellings include Maha Sivaratri.
. It is celebrated every year on the 13th night/14th day of the Maagha or Phalguna month of the Hindu calendar. Since many different calendars are followed by various ethno-linguistic groups of India, the month and the Tithi name are not uniform all over India.
Celebrated in the dark fortnight or Krishna Paksha(waning moon) of the month of Maagha according to the Shalivahana or Gujarati Vikrama or Phalguna according to the Vikrama era.
The festival is principally celebrated by offerings of Bael or Bilva/Vilvam leaves to Lord Shiva, all-day fasting and an all-night-long vigil.
celebrating Mahashivratri, because; there is a legend associated with
Samudra Manthan (churning of ocean), a process in which the asuras
(demons) and the gods joined hands to churn out amrut(nectar) from the
depths of the ocean, using a mountain and a snake as a rope. Among many
things that came out, a pot of poison came out of the ocean. This poison
was so potent that it has the power to destroy the whole universe. Upon
the request of gods, Shiva drank the Halahala to eliminate its
destructive capacity. Shocked by his act, Goddess Parvathi strangled his
neck and hence managed to stop it in his neck itself and prevent it
from spreading all over the universe supposed to be in Shiva's stomach.
Howevever the poison was so potent that it changed the color of His neck
to blue. For this reason, Lord Shiva is also called Neelkanta.
Another version relates that the whole world was facing destruction and Goddess Parvati
worshipped her husband Shiva to save it. She prayed for the jivs
(living souls) remaining in se –- like particles of gold dust in a lump
of wax—during the long period of pralaya
(deluge) night, that they should, upon becoming active again, have His
blessings, but only if they worshipped Him just as she did. Her prayer
was granted. Parvati named the night for the worship of Ishwar by mortals Maha-Sivaratri, or the great night of Shiva, since Pralaya is brought about by Him.