It is difficult to dive below the surface of the Dead Sea because of its massive salt content.
The Dead Sea – which is 45 miles long by nine miles wide – is not a sea but a landlocked salt lake.
The Pacific Ocean is less salty than the Atlantic Ocean.
The warmest ocean on earth is the Persian Gulf – averaging 29-35C (85-96F).
The deepest point in the deepest ocean is Challenger Deep in the Pacific, at almost seven miles.
The Pacific has 46 per cent of the world’s seawater – the Atlantic 23.9 per cent, the Indian 20.3 per cent and the Arctic 3.7 per cent.
All the land mass of the earth could fit into the Pacific Ocean, which covers nearly a complete hemisphere of the earth’s surface.
The Caspian Sea in Russia is actually a lake.
The Red Sea’s name comes from the prolific blooms of algae that die and colour the water.
The busiest ocean is the Atlantic. At 32 million square miles, it is constantly crossed by numerous vessels carrying cargo between the Americas, Africa, and Europe.
The Arctic Ocean is the smallest at five million square miles. It is also the coldest – mostly covered by solid ice, ice floes and icebergs.
The Sea of Azov, a northern section of the Black Sea, is the shallowest – just 13 metres at its deepest.
In the past 100 years, the average sea level has risen between 10cm and 25cm. The level would rise by 66 metres if all the world’s ice melted.