Encircling the Great Stupa is a railing, with four exquisitely carved gateways, or toranas, each facing one of the four cardinal directions. It is believed that these gateways were carved during the Satavahana period sometime around 100 AD. These four gateways are the finest works of art at Sanchi and are among the finest examples of Buddhist art in India. They show scenes from the life of the Buddha and his previous incarnations as Bodhisattvas described in the Jataka tales.