The Guinness Book of Records has named the vast pool beside the sea in Chile as the biggest in the world. It is more than 1,000 yards long, covers 20 acres, has a 15ft deep end and holds 66 million gallons of water.

The pool took five years to build, cost nearly €1billion and the annual maintenance bill will be €2million.
The man-made saltwater lagoon has been attracting huge crowds to the San Alfonso del Mar resort at Algarrobo, on Chile’s southern coast, since its opening. Its turquoise waters are so crystal clear that you can see the lines between the tiles, even in the deep end.

It dwarfs the world’s second biggest pool, the Orthlieb– nicknamed the Big Splash– in Morocco , which is a mere 150 yards long and 100 yards wide. An Olympicsize pool measures some 50 yards by 25 yards.

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 water is amongst the cleanest water on the planet. Of course you can’t drink it because of the salinity, but it’s still cleaner than tap or bottled water

Even in winter the sun warms the water to 26ºC, nine degrees warmer than the adjoining sea.