Stone is a natural building material. It has only to be cut into the shape wanted. There are dozens of kinds of stone. Those used most in building are limestone, marble, granite, sandstone, and slate. Sometimes the stone is not even cut into shape. Rounded stones called field stones make attractive walls.
Wood is another natural building material. There are many kinds of wood to choose from. Fine and oak are common.
Snow, grass, palm leaves, and mud are natural building materials, too. No one had to invent them.
But many of our building materials are manmade. They had to be invented. Brick, steel, glass, concrete, plywood, fiber board, and plaster are a few of them.
Some of the materials used in our buildings do not show after the buildings are finished. In many walls, for instance, rock wool is used to shut heat in during the winter and keep heat out during the summer. It does not show. In the same way, no one would guess to look at the great Empire State Building in New York City that a framework made of 57,000 tons of steel is hidden in its walls.