What causes holes in old concrete statues?

Holes in old concrete statues are typically caused by a combination of weathering, moisture infiltration, and freeze-thaw cycles. Over time, water can seep into the concrete, and when it freezes, it expands, leading to cracks and the eventual disintegration of the material. Additionally, chemical reactions, such as the leaching of calcium carbonate, can contribute to the deterioration. Biological factors, like moss or lichen growth, can also exacerbate the damage by breaking down the concrete structure.