Every year, about the start of monsoons, the natural spring turns red because of iron oxide and "sindoor" (red pigment) anointed by the devotees and temple priests. This is celebrated as a symbol of the menstruating goddess, and as the Ambubachi Mela (also known as "Ambuvaci" or "ameti"), an annual fertility festival held in June. During Ambubachi, a symbolic annual menstruation course of the goddess Kamakhya is worshipped in the Kamakhya Temple. The temple stays closed for three days and then reopens to receive pilgrims and worshippers. The sanctum with the yoni of the goddess is one of the most important pilgrimage sites for the Shakti tradition, attracting between 70,000 to 200,000 pilgrims during the "Ambubachi Mela" alone from the northeastern and eastern states of India such as West Bengal, Bihar and Uttar Pradesh. It also attracts yogis, tantrikas, sadhus, aghoris as well as other monks and nuns from all over India.