World's Largest Swimming Pool

Located between Chile's San Alfonso del Mar Resort and the sea, the World's Largest Swimming Pool essentially converts the salty public waters of the ocean to a pristine private lake.

At over 1,000 yards long and 115 feet deep at its deepest point, the resort's 20-acre pool cost around a billion dollars to build and stares down a $2 million annual upkeep bill. Despite the unlimited natural waters of the ocean which sit just over the pool wall, the resort uses state-of-the-art technology provided by a company that prides itself on being able to create swimming pools of any size, to constantly pump and filter sea water into the private lagoon and alternately back out to sea.

The system also cleans the water once again before returning it to the ocean, lessening the environmental impact, but the conversion seems a bit drastic simply to provide crystal clear waters.