In Greece, the iconic whitewashed island house has a public health angle to it. "In 1938, a national order mandated the painting of island homes in blue and white. At the time, Greece was suffering an outbreak of cholera during the dictatorship of Ioannis Metaxas. In an effort to curb the disease, he ordered citizens to whitewash their homes. This might sound strange today, but the whitewash used to paint the houses contained limestone. Limestone is a powerful disinfectant, and not many others were in common use at the time. Greek citizens thus whitewashed their homes to help sanitize them and reduce the spread of cholera." and older