The town is noted for its white and blue domed houses. The houses are painted in white lime water so that the rainwater which falls over it runs down and can be collected. The other reason for painting the houses white is for aesthetic purposes. The other explanation given is that during the Ottoman rule of Greece, which lasted for over 400 years, Greeks were not allowed to fly their white flag. In defiance, in Oia they painted their entire housing complex in white with domes giving the village an effective white perspective and elegance. Impressive houses in the town are those "cliff houses" built in the niches carved into the caldera slopes with provision of air-filled pumice which provides insulation benefits to the building, keeping it warm in winter and cool in summer.