Pottery is one of the oldest and most widespread forms of art in China. It dates back to the Paleolithic era, when the first clay vessels were made by hand and fired in open pits. Since then, Chinese pottery has developed into a rich and diverse tradition, with different types of clay, firing techniques, shapes, decorations, and functions. Some of the most famous types of Chinese pottery are painted pottery, which has colorful geometric or animal motifs; celadon, which has a jade-like green glaze; blue and white porcelain, which has intricate patterns painted with cobalt blue under a clear glaze; and imperial porcelain, which was made exclusively for the emperors and their courts. Chinese pottery has influenced the ceramic arts of many other cultures.