It is the world's largest swimming pool and is more than 1,000 yards long, it covers 20 acres, has a 115ft deep end and holds 66 million gallons of water.

The Guinness Book of Records named the vast pool beside the sea in Chile as the biggest in the world.

Chile's monster pool uses a computer- controlled suction and filtration system to keep fresh seawater in permanent circulation, drawing it in from the ocean at one end and pumping it out at the other.

The sun warms the water to 26c, nine degrees warmer than the adjoining sea.

Chilean biochemist Fernando Fischmann, whose Crystal Lagoons Corporation designed the pool, said advanced engineering meant his company could build "an impressive artificial paradise" even in inhospitable areas.

"As long as we have access to unlimited seawater, we can make it work, and it causes no damage to the ocean."