The Nilachal Hill situated at a distance of 7 km from Guwahati is of great historical, archeological as well as religious importance. This hill believed to be a 'Khasi' sacrificial site earlier, now has a group of ancient temples on the top; the largely eminent of them is the Kamakhya temple. The temple of Goddess Shakti or Kamakshya is the oldest and most revered centre for Shakti worship leading to the spread of the sect Tantrik Hinduism.
The temple was built by the king of the Koch Dynasty in 1565. Its architecture reflects the perfect form of the medieval architectural style. The temple was destroyed in the 16th century itself and was rebuilt in the 17th century by the king Nara Naryana of Cooch Bihar.
The Kamakhya Temple has a unique beehive-like shikhara. The temple houses beautiful images of lord Ganesha and other Hindu Gods and Goddesses outside it. The panels are amazingly decorated with sculptures. The walls of the temple depict images of Naranarayana and other Hindu gods. The sanctum sanctorum of the temple is fashioned in the form of a cave. It houses only an underground spring which is worshipped by the devotees. Ambubashi festival is the annual festival celebrated with deep faith at the temple. Several tantriks from across the country flock to the temple for Puja. Manasha Puja and Durga Puja are the other two festivals celebrated every year.
It is believed that female genitalia (yoni) of dead Sati fell down while her corpse was being carried by her husband Shiva turning the hill blue, therefore the name Neelachal (Blue Spread). This 10th century temple was reconstructed after being destroyed by Muslim rulers.