Badab-e Surt is a series of terraced travertine (limestone) pools – smaller than those at Turkey's Pamukkale, but more colourful and serenely isolated within a mountain-ringed valley, 23km east of the Damghan–Sari road turning at Telma Dareh.
The nearest village is Orost. From a junction 1km before that village, it's 3km on an unpaved road (OK by car when dry, but a 4WD is needed after rain) to a lonely whitewashed box-building at the base of the Badab-e Surt hill. From there the walk up takes around 25 minutes; otherwise a waiting tractor driver will offer to take you the longer way by road (2km more) for IR400,000 including waiting.