Where Shohada St approaches the arid crags that abruptly mark the city's eastern edge sits this hefty octagonal structure of mysterious provenance. Some scholars date it to the 2nd century AD and think it may have been an observatory; others say it was a tomb. Whatever its function, it's unusual hereabouts for being constructed mostly of stone – though the double-layered dome, added 150 years ago, is brick.
Today it houses a museum of old gravestones. (Be careful not to photograph the neighbouring army base!) Across the ring road from the tower, Shohada St continues east through a large park towards the eye-catching new Saheb Zaman Mosque.
Shuttle taxis from Shohada Sq head this way.