Cities around the world buried rivers to tackle pollution, expand urban areas and build early sewer systems. In Sheffield, England, many waterways were covered between the 1860s and 1910s, but the city is now investing millions to uncover parts of the River Sheaf. Known as “daylighting” or de-culverting, the process aims to reduce flood risk, restore ecosystems and help cities adapt to climate change. Experts say open rivers can improve biodiversity, cool urban areas and make communities more resilient, though projects are costly, technically complex and can face delays.