This is the most conspicuous structure at Sarnath. Colonel Cunningham bore a shaft from the top centre of the stupa and discovered a stone tablet on which an inscription is written with the word Dhamekha, and mentions that this is the spot where the Buddha delivered his first sermon.
Dhamekha seems to be a distorted form of Dharma Chakra which means turning the wheel of the Dharma. It is also said that at this spot the five ascetics who left Gautama Buddha in Bodh Gaya used to live in huts. The original stupa was constructed by Ashoka. The present size of the stupa is 31.3 m high and 28.3 m in diameter. The lower portion of the stupa is covered completely with beautifully carved stones. The design consists of a broad band of Swastika (fylfot) carved in different geometrical patterns with a finely chiselled lotus wreath, running over and below the swastikas.
The Dhamekha stupa is considered to be the sacred place where the voice of Buddhism was first heard. Many dignitaries of Buddhist countries visit this place for circumambulation of this sacred stupa and to worship the Buddha. Tibetans Buddhist circumambulate it chanting the mantra 'Om mani padme hum'. The first discourse of the Buddha was on the 'Wheel of Law'. The wheel symbolises samsara (world), the eternal round of existence which goes on and on, life after life because of ceaseless cravings and desire.