San Alfon­so Del Mar is cur­rent­ly the sec­ond largest swim­ming pool in the world and sits on a pri­vate resort in Algar­robo. With a length of over nine foot­ball fields, this enor­mous salt­wa­ter pool is filled with over 66 mil­lion gal­lons of water. At the time of its com­ple­tion in 2006, San Alfon­so Del Mar cap­tured the record for the world’s largest pool and held it for almost a decade.