Why the Dead Sea is called the 'Dead '?

It's called the Dead Sea because nothing lives in it. It is one of the saltiest water bodies in the world, almost six times as salty as an ocean. It is completely landlocked and gets saltier with increasing depth. Salt actually precipitates out and piles up on the bottom of the sea. White crystals of mineral salts cover everything on its shores. The water in it is deadly to many living things. Fish accidentally swimming into it get killed instantly. In fact there is no seaweed or plants or any kind of creature living in or near the water. But humans are remarkably adaptable. In fact our bodies are more buoyant in the Dead Sea, such that we can float on it as seen in the picture below. Reason is its high density because of high concentration of dissolved mineral salts. 

A natural question from an inquisitive mind will be - Why such high saline levels? The Dead Sea is continually fed water from the rivers and streams coming down off the mountains that surround it. But no rivers drain out of the Dead Sea. The only way water gets out of it is through evaporation. When the water evaporates, it leaves behind the dissolved minerals making it saltier.

There are few important uses of Dead Sea worth mentioning. It was one of the world's first health resorts and has been the supplier of a wide variety of products, - from balms for Egyptian mummification to potash for fertilizers. People also use the salt and the minerals from the Dead Sea to create cosmetics and herbal sachets.

References:
http://www.extremescience.com
http://en.wikipedia.org/wiki/Dead_Sea