Cambodia

Angkor Wat stands on sand. And that sand needs to stay wet.

Beneath the enormous stone structures lies a foundation of sand. Khmer builders removed the natural soil, replaced it with sand and used water to make the layer stable enough to carry the weight of the temple.

The moats around the temples were not only decorative or religious. They also helped maintain groundwater levels and keep the sand beneath the buildings stable.

That relationship still matters. If the groundwater drops too far, the sandy foundation can settle and damage the temples.