Shivaratri falls on the day of the dark half of the month of Falgun. This is a festival observed in honour of Lord Shiva. Shiva was married to Parvati on this day. Devotees observe a strict fast on this day and keep vigil all night.

The Shiva Lingam is worshipped throughout the night by washing it

every three hours with milk, curd, honey, rose water, etc., whilst the chanting of the Mantra Om Namah Shivaya continues. Offerings of bael leaves are made to the Lingam.

Hymns in praise of Lord Shiva, such as the Shiva Mahimna Stotra of Pushpadanta or Ravana’s Shiva Tandava Stotra are sung with great fervour and devotion. He who utters the names of Shiva during Shivaratri, with perfect devotion and concentration, is freed from all sins. He reaches the abode of Shiva and is liberated from the wheel of births and deaths.

Many pilgrims flock to the places where there are Shiva temples.

In the Shanti Parva of the Mahabharata, Bhishma, whilst resting on the bed of arrows and discoursing on Dharma, refers to the observance of Maha Shivaratri by King Chitrabhanu.

The story goes as follows. Once upon a time King Chitrabhanu of the Ikshvaku dynasty, who ruled over the whole of Jambudvipa, was observing a fast with his wife, it being the day of Maha Shivaratri. The sage Ashtavakra came on a visit to the court of the king. The sage asked, “O king! why are you observing a fast today?” — Dishq.org