Maha-shiV-Ratri will be celebrated all around in Bharat to mark the union of shiV and parVati. Parvati is the one who is born again and again on earth as matsya kanya, as sati, as parvati, as uma and then with her one-pointed devotion crosses the mountain (parvat) to be one with her lord, shiv.
Shiv is the highest state that a yogi attains while practising yog in its purest divine form, before merging into lordship and being lord oneself.
Shiv is the north, Ra, Sahastrar, Parvati is the south, Ke, Mooladhar. Merging of the energy of serpent energy kundalini into Sahastrar is Mahashivratri. It's only possible with the step by step hand-holding by a worthy g-uru while imparting the knowledge and this leads one to the highest of the highest state shiv, to the ultimate liberation, to be healed & to heal many effortlessly without any barrier, limitations & boundaries.
Thats why Mahashivratri is celebrated when Sun (Ra) enters the zodiac Kumbh (Aquarius), the celestial knowledge, in the nakshatra Shatabhisha, the constellation of hundred healers. Sun (shiv) and Moon (parvati) are exact 18 degrees apart, which implies the distance of Ra.
People all across will pour water, milk, belpatra on shivlingam but only a tapasvi like parvati knows that the spine is the path to shivlingam pineal, ahead of which sits the mahayogi shiv to be merged into. While rest of the world will be busy playing with hinting significances of this day, a yogi merges into the guru agnya (instructions of guru) to be one with ultimate lord. While other beings remain busy drinking cannabis & dancing while thinking to participate in the wedding of shiv & parvati, forgetting it were ghosts & animals who participated in the wedding while divine beings and devatas witnessed the whole communion.
This states that one must involve in penance and knowledge while leaving all what makes one drown into the allurements of this earthly world, while not forgetting the purpose of this bearth.