Badab-e Surt

High in the mountains south-east of Sari, near the villages of Orost and Surt, a hillside falls away in a staircase of shallow pools, each rimmed with stone and stained in shades of orange, red and cream. This is Badab-e Surt, one of the most striking natural sites in Iran, created over thousands of years by the water of two mineral springs.

Its name joins the Persian words bad, gas, and ab, water: “gassy water”, a description of the springs that bubble up at about 1,840 metres above sea level. As their water flows downhill and cools, it leaves behind layers of carbonate minerals, slowly building the terraces of travertine that step down the slope. One spring is very salty and gathers in a small pool, traditionally believed to help with rheumatism and some skin complaints. The other has a sour taste, and the iron oxide in its water gives the terraces their famous orange colour.

Natural terraces like these are rare, and Badab-e Surt is often compared to Pamukkale in Turkey, though it is smaller and far wilder. There are no hotels at the site: visitors walk up from the road, or ride the last stretch on a tractor, and the best light is at sunset, when the pools catch the colours of the sky.

The terraces are delicate, and visitors are asked to keep off the rims and not to walk in the pools. The surrounding mountains, with their forests on the northern slopes and drier hills to the south, make the journey part of the reward.