The traditional architecture of Santorini is similar to that of the other Cyclades, with low-lying cubical houses, made of local stone and whitewashed or limewashed with various volcanic ashes used as colours. The unique characteristic is the common utilisation of the hypóskapha: extensions of houses dug sideways or downwards into the surrounding pumice. These rooms are prized because of the high insulation provided by the air-filled pumice, and are used as living quarters of unique coolness in the summer and warmth in the winter. These are premium storage space for produce, especially for wine cellaring: the Kánava wineries of Santorini.