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10 Most Expensive Pools

Hearst Castle
The indoor pool at Hearst Castle
The indoor pool at Hearst Castle
Jim Steinfeldt/Michaelochs Archives/Getty Images

California's Hearst Castle is home to two luxury pools that are arguably the most famous swimming pools in the world. The Neptune pool is located outdoors, and measures 104 feet by 58 feet (32 by 18 meters), while the indoor Roman pool is slightly smaller. Built between 1924 and 1936, the entire property, including both pools and all furnishings cost less than $10 million [source: Hearst Castle/California State Parks]. Today, these pools would be difficult to replicate at any price. They're designed to resemble ancient Roman baths and are filled with priceless marble and intricate tile mosaics. Both pools are lined with great works of art that were commissioned by the Hearst family, including statues by Italian master craftsmen. The entire Neptune pool area, including the walls, ceilings and the pool itself are covered with thousands of mosaic tiles lined with gold [source: Hearst Castle/California State Parks].

Visitors can tour the mansion year-round, with day and evening tours available. But what if you want to take a dip in one of these famous pools? Several times a year, the mansion holds benefit auctions where visitors can bid for a chance to spend an evening on the property or go for a swim in the pools.