The spot between the eyebrows is the seat of the sixth chakra- Ajna as well as of the third eye of Consciousness; an eye, which is not sullied by karmic memory or samskaras.
According to Hindu philosophy, applying tilak on the forehead reinforces our connection with the divine and reminds us of our true-life purpose, which is moksha- i.e. freedom from these cycles of birth and death.
Over the years, in the Indian sub-continent, tilak was applied to wish good luck before any important event or before going on any important journey and welcoming someone by applying a tilak was done to mark and celebrate their successful and victorious return, their accomplishment.
In this way, there are many spiritual and cultural significations to why Hindus and several other cultures in the Indian sub-continent apply tilak on their forehead.
From spiritual or cultural viewpoint, however we look at it; we find that applying tilak on one’s forehead brings great benefits. Something to think about and adopt, so as to enhance our conscious lifestyle.