The Great Stupa is the centrepiece of Sanchi and one of the oldest stone structures in India. Built originally by the Emperor Ashoka in the 3rd century BC, it was later enlarged to its current form: a massive hemispherical dome 36 metres in diameter and 16 metres high, topped by a triple parasol representing the Three Jewels of Buddhism. The dome is solid — there is no interior to enter.
What makes the stupa extraordinary are the four elaborately carved gateways (toranas), each about 10 metres high, standing at the cardinal points around the structure. Their beams and pillars are covered with scenes from the Jataka tales — stories of the Buddha's previous lives — as well as episodes from his last life and the history of Buddhism in India. The scenes are so densely packed with figures, animals, plants, and architectural settings that hours of study barely exhaust them. The Buddha himself is never depicted in human form in the earliest carvings; his presence is indicated instead by symbols — a footprint, a parasol, an empty throne.
Walk around the stupa in a clockwise direction following the pradakshina path, the traditional direction of circumambulation. Each of the four gateways deserves extended attention.