Sunbathing is mainly to let the sun shine on the human skin, causing a series of physical and chemical reactions to achieve the purpose of fitness and treatment, and is often used in conjunction with cold water bath and air bath. With the development of science and technology, sunbathing can be divided into natural sunbathing and artificial sunbathing. Sunbathing is also called tanning. Excessive exposure will form sunburn, which is called "sunburn". The earliest origin of tanning is like its name "tanning"-sunbathing. Tanning appeared in the west in the middle of last century, representing a sunbathing culture of Europeans and Americans-enjoying the sunshine. Suntan and vacation are directly linked, and vacation cannot be separated from sunny beaches. Suntan has almost become a status symbol. People with bronzed skin show that they often go to sunny and expensive resorts to bask in the sun, so "dark skin" is the best business card to show their identity.