The Dead Sea, which is the lowest body of water in the world, is a landlocked salty lake forming part of the border between Israel and Jordan.
Located in an area with extremely hot weather, where summer temperatures exceed 40 degrees Celsius, the lake loses 1.37 metres a year to evaporation.
The salt which remains makes the water 10 times as salty as the ocean and gives great buoyancy. It means you can float easily on the water even if you are a poor swimmer. When you come out of the lake, the water evaporates almost instantly leaving crystals of salt on your skin.
Few plants can grow around the lake and no fish or animals can survive in the water - only bacteria live there. While the Dead Sea is natural, there are more and more 'dead seas' because we are constantly polluting the oceans.
In Hong Kong the many summer red tides caused by pollution result in fish and shellfish being poisoned. Eating such contaminated seafood is obviously dangerous.