Blackhouses were a traditional form of building in the Scottish Highlands, the Hebridean islands and Ireland, originating more than 1000 years ago. Those on the Outer Hebridean island of Lewis were built of two dry-stone walls with earth packed inbetween. The inner stone wall supported wooden rafters covered by a thatched roof of turf and cereal straw. The roof was low, rounded, and often roped, to resist damage from the strong prevailing westerly winds off the Atlantic Ocean. A single door led to a cattle byre at one end and human quarters with a central fire at the other. There was no chimney - the smoke from the fire simply filtered through the roof.