A recent study published in *Current Biology* reveals that humans possess a 'third eye' known as the pineal gland, which is a remnant of an ancient organ that played a significant role in the lives of early non-vertebrate ancestors. Researchers from the University of Sussex and other institutions found that this gland, located in the middle of the human brain, no longer functions as a visual organ but is crucial for regulating sleep through the production of melatonin. This hormone helps synchronize circadian rhythms, influencing sleep patterns and various physiological processes such as reproductive health and immune function. The research indicates that the pineal gland and the retina share a common evolutionary origin, with early ancestors losing their side eyes and relying on this central structure for light detection. While some species still have a visible third eye, the human version has been linked to cultural beliefs surrounding intuition and spiritual insight, particularly in Hindu practices related to the 'Ajna chakra.'