Window sills and cornices
Cornices are an old and important design element in European architecture. They also have a purpose in terms of construction by protecting the wall below from weathering. This is why they are also called roofing when they are above doors and windows. Cornices are combined with vertical design elements such as pilasters and columns, which in turn rest on the outside window ledge.
An exterior windowsill also serves the structural protection of the facade below. It is tilted to the outside and has a drip edge on the underside that prevents rainwater flowing onto the facade and leaving drip traces behind.
Indoor windowsills are however only an optical element and are installed horizontally. Their shape and depth depend on the thickness of the wall, the position of the window and the intended use. Mostly, they are used as place to show and store items, if deep enough.