The crown chakra, or thousand-petaled lotus, is called sahasrara chakra; located at the top of the head.When the coiled serpent of kundalini energy is moved upward from the base of the spine and unites with this chakra, then all duality is banished and the yogi exists in deep connection with all that is. The seventh center integrates all the chakras with their respective qualities. It is the last milestone of the evolution of human awareness. Nowadays, we are at a level which corresponds to this chakra, and our consciousness is able to easily enter into this new realm of perception, which is beyond our limited mind and concepts, and which becomes absolute at the level of the Sahasrara. This chakra gives us the direct, absolute perception of Reality on our central nervous system.
This is precisely what is achieved by Self Realization, through the spontaneous awakening of the Kundalini through daily yoga.