|ॐ नमः शिवाय|
Maha Shivaratri is a Hindu festival celebrated annually in honour of the god Shiva. There is a Shivaratri in every luni-solar month of the Hindu calendar, on the month's 13th night /14th day, but once a year in late winter (February/March, or Phalguna) and before the arrival of spring, marks Maha Shivaratri which means "the Great Night of Shiva".
Read more at: Maha Shivaratri
write up courtesy: https://en.wikipedia.org/wiki/Maha_Shivaratri