Poson, the full-moon festival commemorates the advent of Buddhism to Sri Lanka in the 3rd century BC. The day is celebrated with religious observances. The centre of festivities is at Mihintale, about 12 kilometers from Anuradhapura where the Buddhist doctrine was
first preached by Arahat Mahinda, son of the great Emperor Asoka of India. Apart from religious festivals there are illuminations and decorations and processions in various parts of the island.