What is the third eye?

After omming with Hamatsa, I thought it might be interesting to do a little research and find out more about the third eye. Here's what wikipedia has to say about it:

The third eye (also known as the inner eye) is a metaphysical and esoteric concept referring in part to the ajna chakra in certain Eastern and Western spiritual traditions. It is also spoken of as the gate that leads within to inner realms and spaces of higher consciousness. In New Age spirituality, the third eye may alternately symbolize a state of enlightenment or the evocation of mental images having deeply-personal spiritual or psychological significance. The third eye is often associated with visions, clairvoyance, precognition, and out-of-body experiences, and people who have developed the capacity to use their third eyes are sometimes known as seers.

In Hinduism and Buddhism, the third eye is a symbol of enlightenment. In the Indian tradition, it is referred to as the jnana-chaksu, the eye of knowledge, which is the seat of the 'teacher inside' or antar-guru. The third eye is the sixth chakra. This is commonly denoted in Indian and East Asian iconography with a dot, eye or mark on the forehead of deities or enlightened beings, such as Shiva, the Buddha, or any number of yogis, sages and bodhisattvas. This symbol is called the "Third Eye" or "Eye of Wisdom", or, in Buddhism, the urna. In Hinduism, it is believed that the opening of Shiva's third eye causes the eventual destruction of the universe.

In the Upanishads, a human being is likened to a city with ten gates. Nine gates (eyes, nostrils, ears, mouth, urethra, anus) lead outside to the sensory world. The third eye is the tenth gate and leads to inner realms housing myriad spaces of consciousness.

According to Max Heindel's Rosicrucian writings, called Western Wisdom Teachings, there are in the brain two small organs called the pituitary body and the pineal gland. This last gland is also called by medical science as "the atrophied third eye"; however, these teachings describe that none of them are atrophying: the pituitary body and the pineal gland at the present time are neither evolving nor degenerating, but are dormant. It is said that in the far past, when man was in touch with the inner worlds, these organs were his means of ingress thereto, and they will again serve that purpose at a later stage.

According to this view, they were connected with the involuntary or sympathetic nervous system and to regain contact with the inner worlds (to reawaken the pituitary body and the pineal gland) it is necessary to establish the connection of the pineal gland and the pituitary body with the cerebrospinal nervous system. It is said that when that is accomplished, man will again possess the faculty of perception in the higher worlds (i.e. clairvoyance), but on a grander scale than it was in the distant past, because it will be in connection with the voluntary nervous system and therefore under the control of his will.