The earliest ceramics made by humans were pottery objects (i.e. pots or vessels) or figurines made from clay, either by itself or mixed with other materials then hardened, or sintered, by fire. Later ceramics were glazed with ceramic coatings to change the look of the piece, and then fired in a kiln to create smooth, colored surfaces. These ceramic coatings also made the vessels more water-tight. Today, ceramics now include domestic, industrial and building products, as well as a wide range of ceramic art.