Chakras are centres of energy which govern certain zones of the body; they convey energy between dimensions (or planes of existence) and are centres of subtle forces, the generation of prana (energy) and higher consciousness.
Sahasrara is located at the crown of the head or is sometimes considered to be above the physical body. Its lotus contains a thousand petals, of which five represent all the letters of the Sanskrit alphabet. Through this chakra, universal existence, with no boundaries of “I” consciousness in the body, is realised.
Parambrahma rules this chakra, symbolised by the triangle of consciousness (called Veeja). This centre represents the overcoming of obstacles, and merging into the void, or the supreme light beyond form, an experience beyond description, according to most yogic scriptures and saints.
Meditating here enables one to cross the boundaries of creation, preservation and destruction so you can taste the sweet nectar (amrita) that flows in a constant stream from Sahasrara. One is no longer subjected to birth or death. At this state of awakening, individual identity disappears forever and one identifies with supreme consciousness. Remember that the deathless state does not mean one will never leave the body, but rather that the conscious mind merging with the infinite is achieved as a permanent state which will not be disrupted by the body dying.
Information source: Energies of Transformation, A Guide to the Kundalini Process, by Bonnie Greenwell PhD.