Look at this landscape and you would never guess what was under it. The land south of Lößnitz and around Bad Schlema is green, pretty and slightly hilly, a foothill of the Ore Mountains with small towns, orchards and the Zwickauer Mulde river slipping through. But between 1946 and 1990 this was the heart of the Wismut mining company, a Soviet-German enterprise that dug uranium on a huge scale for the Soviet atomic programme. East Germany became one of the world's largest uranium producers, and the work left deep shafts, tall spoil heaps and a population who knew what their work was for and rarely spoke about it.
The irony is that the same rock had made Schlema famous decades earlier as a radon spa. Before the Second World War, visitors came to Oberschlema to take the radioactive waters, and the spa was briefly the richest radium resort anywhere. After the war the Soviets mined the town itself, and entire streets disappeared into subsidence. Today Bad Schlema has been rebuilt with a landscaped park laid over the old workings, and the spa has returned, with radon baths and a good thermal pool. You can take the cure, if you like, in a place that was once the most polluted in the region.
The Wismut clean-up, finished largely by the 2010s, is among the biggest environmental recovery projects Europe has carried out, and the old spoil heaps now sit under grass and young woods. Information boards and walking routes explain the story honestly. Visitors who want to understand more can visit the mining museum in Bad Schlema or take a guided tour underground at certain locations.
On the bike, the roads between Lößnitz, Hartenstein and Bad Schlema are quiet country lanes with gentle bends, and the Mulde valley is a pleasure in autumn. Lößnitz has petrol and supermarkets, with Hartenstein and its castle, Stein, a short ride away. Plan the visit for a clear day, because the heaps look best against sky, and take time to read the signs. They explain what the land has been through, which is more than most places will tell you.