The most impressive artificial paradise, with a length of 1,000 yards, an area of 20 acres, and a maximum depth of 115 feet, can be found in Algarrobo city on the Pacific coast. It was named by the Guinness Book of Records as the World's largest swimming pool, with a length of 1,000 yards, an area of 20 acres, and a maximum depth of 115 feet. It can contain nearly 66 million gallons of crystal clean saltwater. The pool opened in December 2006 after five years of building work at a cost of about one billion dollars ($US) and an annual maintenance cost of roughly two million.