San Alfonso del Mar Lagoon

The San Alfonso del Mar lagoon is a huge turquoise swimming lagoon at a private resort in Algarrobo, Chile, about 100 kilometres west of Santiago on the Pacific coast. When it was finished in 2006, it was recorded by Guinness World Records as the largest swimming pool in the world.

The pool is about 1,013 metres long and covers 8.2 hectares. It holds about 250 million litres of seawater, pumped from the nearby ocean and then filtered and treated. It opened in December 2006 and the water is kept clear using a method developed by the company Crystal Lagoons. The resort around it has about 1,200 second homes.

How big is it?

Its water is clear and blue like a tropical bay, and the deepest part is reported to be about 35 metres (115 feet), though one English source prints 11.5 feet. The lagoon is ringed by white terraced apartment buildings.

Only people who live at the resort can use it, so it is a private lagoon, not a public beach.

Who built it?

The lagoon was developed by Crystal Lagoons, a company created by Fernando Fischmann, with the developer Inmobiliaria El Plomo and the architects Marques + Garcés.

The resort also has about 1,200 holiday homes, an aquarium café, a beach club with a glass pyramid over a heated pool, and a pyramid-shaped apartment building.

Still the biggest?

Guinness recorded it as the largest swimming pool by area when it was finished. Since then others have come close or passed it. Wikipedia's list of largest pools now ranks Citystars in Sharm El Sheikh, Egypt, first at about 96,800 square metres and San Alfonso del Mar second at about 80,000. Sources also differ on the pool's exact size, giving between 7.7 and 8.2 hectares. Crystal Lagoons says its treatment uses far fewer chemicals than a normal pool, but that is the company's own claim.

On the globe

The model shows the long turquoise lagoon ringed by white terraced towers. Look at how the pool stretches along the shore.