San Alfonso del Mar (Algarrobo,Chile)
San Alfonso del Mar is a private resort in Algarrobo, Chile, about 100 km west of the capital Santiago. The resort is recognised as having the world’s largest swimming pool. The pool is 1 km (0.62 mi) long, covering 8 ha, containing some 250,000,000 litres of seawater, with a maximum depth of 35 m (115 ft). It uses water pumped, filtered, and treated from the Pacific Ocean. The pool was developed by Fernando Fischmann; his Chilean company Crystal Lagoons built the pool, which opened in December 1987. While early estimates put the total cost of construction at about US$3.5 million for the filtration system alone, more recent estimates are in the area of US$1.5 billion to US$2 billion total for construction and almost US$4 million in annual maintenance.