Northern Europeans spend a lot of time in their summer holidays.Because they know that a certain amount of sunshine is good for their bodiesand general health.
In ancient Greece people knew about the healing powers of the sun,but this knowledge was list .At the end of the nineteenth century a Danish doctor, Niels Finsen,began to study the effect of sunlight on certain diseases,especially diseases of the skin.He was interested not only in natural sunlight but alsi in artificially produced rays.Sunlight began to play a more important part in curing sick people.
In winter,wearing only shorts,socks and boots is OK.Although you wore hardly any clothes,but you would seldom felt cold.That was because you body was full of energy which you got from the sun .But the doctor knew that sunshine can also be dangerous. If ,for example ,tuberculosis is attacking the lungs unwise sunbathing may do great harm.