Maha Shivratri or Maha Sivaratri or Shivaratri or Sivarathri (Great Night of Shiva or Night of Shiva) is a Hindu

Hinduism

Hinduism is the predominant and indigenous religious tradition of the Indian Subcontinent. Hinduism is known to its followers as , amongst many other expressions...

 festival celebrated every year on the 13th night/14th day in the Krishna Paksha (waning moon) of the month of Maagha

Maagha

Maagha is a month of the Hindu calendar. In India's national civil calendar, Maagh is the eleventh month of the year, beginning in January and ending in February....

 (as per Shalivahana or Gujarati Vikrama) or Phalguna

Phalguna

Phalguna is a month of the Hindu calendar. In India's national civil calendar, Phaalgun is the twelfth month of the year, beginning on 20 February and ending on 21 March .In lunar religious calendars, Phaalgun may begin on either the new moon or the full moon...

 (as per Vikrama) in the Hindu Calendar

Hindu calendar

The hindu calendar used in ancient times has undergone many changes in the process of regionalization, and today there are several regional Indian calendars, as well as an Indian national calendar. Nepali calendar, Bengali calendar, Malayalam calendar, Tamil calendar, Telugu calendar, Kannada...

 (that is, the night before and day of the new moon). The festival is principally celebrated by offerings of Bael

Bael

Bael Bael (Aegle marmelos) Bael (Aegle marmelos) (Bengal quince, stone apple, Sanskrit : विल्व, Malayalam: കൂവളം, Bengali: বেল, Hindi: बेल (Sirphal), Marathi: बेल or कवीठ (Kaveeth), , Sindhi: ڪاٺ گدرو , Sinhalese: beli, Tamil: வில்வம் is a species of tree native to India...

 (Bilva) leaves to the Lord Shiva, all day fasting and an all night long vigil.