[DanBC]

Because homes are built out of different materials. Stone houses get whitewashed. White wash is a very thin plaster - lime, salt, water, sometimes molasses.

One Indian town - Jaipur - has pink houses. This is because of the local stone, and because they painted everything pink when Prince Albert went to visit. It's pink! (http://www.sherwin-williams.com/homeowners/color/find-and-ex...)

(http://commons.wikimedia.org/wiki/File:Jaipur_city_palace_in...)