The houses in Babylon had open roofs, so that on hot nights, the family could sleep there. The living rooms, dining rooms, and the kitchens were, of course, downstairs. Lamps burned with olive oil, and every house had a chapel for burial and worship ceremonies. Since Mesopotamia had only clay for use in building, the strong wooden supports for the houses were imported from Lebanon. Eventually, people began baking their bricks and improved the strength of their buildings.