Gruener Heiner is an artificial hill that has become a modest but useful viewpoint over the Stuttgart region. The slope was built from rubble and excavated material, then softened into grassland, paths, and a wind turbine that makes it visible from a distance.
It is not a headline sight, but it gives a different angle on Stuttgart: vineyards, suburbs, industry, and the folds of the Neckar basin all in one sweep. Come on a clear day, bring shoes for a short climb, and treat it as a fresh-air break from museums and traffic.