46 km north of Bhopal, the capital of M.P., beside the main railway line, the great Sanchi Stupa sits on a gently rising hill. It was originally constructed by Emperor Ashoka in the 3rd century B.C., and later extended. It is 16 metres high and 37 metres in diametre, with a railing surrounding it. There are four gateways to it through four toranas or gateways, which are themselves masterpieces of Buddhist art. They were erected around 35 B.C. and have triple architraves supported full of carvings from Buddha's previous lives, that is, the Jataka tales. The best preserved is the northern gateway, upholding a broken wheel of law, whereas the oldest is the southern gateway. Several pillars stand around. Pillar No.10  was erected by Emperor Ashoka himself and is close to the southern entrance to the great stupa. Halfway down the hill to the west, sits a second stupa , with `medallions' decorating the surrounding walls with  lovely motifs. It contained relics of important Buddhist teachers, and it is because the teachers were lower in stature to the Buddha and his direct disciple, that this stupa is  positioned lower than the great stupa. The third stupa stands north-east of the main stupa and although smaller , resembles the great one. It once contained the relics of two of Buddha's most important disciples. There are two other big stupas , one of them in very bad condition, and many small ones – some less than a metre high. To the south of the great stupa is a chaitya or hall, and a smaller temple, both reminiscent of Greek architecture. There are traces of wooden viharas or monasteries on the site.