The Yuncheng Salt Lake — also called the Hedong Salt Pond — is one of the oldest continuously exploited saltworks in the world, with a production history of over 4,600 years. The lake sits in a basin south of the city, enclosed by dikes that separate it from the surrounding agricultural land. In summer — typically June through September — the combination of salt-tolerant algae, halobacteria, and Dunaliella algae turns sections of the water vivid red, pink, and green, producing a landscape that is startling in the flat yellow plain.
The salt is still produced here commercially, and the traditional extraction method — flooding shallow evaporation pans and raking the crystallised salt — is still used alongside modern equipment. A visitor area allows viewing of both the coloured water and the salt production operations. The surrounding dikes and channels form a pattern visible from slightly elevated ground that reveals the centuries of hydraulic engineering built to manage the lake. Early morning provides the most saturated colour and fewest visitors.