Acid rain can ruin buildings and statues by stripping away the stone that was used to make those structures. Limestone and marble were common materials used to make parts of buildings and whole statues that were meant to be exposed to the outdoors. To the surprise of architects, the acid in acid rain could turn the calcium carbonate molecules that made up the stone materials into calcium sulfate molecules. Because calcium sulfate can be dissolved by water, acid rain would eventually wash away the outsides of buildings and statues -- like a glass of water does to a cube of sugar.
Buildings can be damaged by acid rain because it dissolves the stone or corrodes the metal that is exposed to the weather. Before people became aware of the problems that acid rain could cause for buildings, they used limestone and marble as building material that would be exposed to rain and fog. These types of material contain calcium carbonate or calcium-based compounds, which can be dissolved by acid rain. Sandstone is more resistant to being dissolved by acid rain, but black deposits can form on the outside of it over time
