Houses of the rich and upper classes were lavish. The atrium was the most important part of the house. It was where guests were greeted. The atrium was open in the centre, surrounded at least in part by porticoes with high ceilings, that often contained only a little furniture to give the effect of a large space. In the centre was a square roof opening in which rainwater could come, draining inwards from the slanted tiled roof. There were kitchens, bedrooms, a dining room, and a number of open rooms.