The largest swimming pool in the world is at the San Alfonso del Mar resort in Algarrobo, Chile. This outdoor pool is 8/10 of a mile (1.3 kilometers) long. With a crushed quartz beach, an artificial volcano and waves for surfing, the Ocean Dome at Miyazaki, Japan's Sheraton Seagaia Resort is the world's largest indoor pool.
At 108 feet (33 meters) deep and containing underwater rooms and tunnels, Brussels, Belgium's Nemo 33 is the world's deepest man-made pool. The outdoor Neptune pool and indoor Roman pool at Hearst Castle in California, designed to look like ancient Roman baths, may be the world's most famous pools. The chance to swim in them is auctioned off.
One of the most expensive private pools ever built, owned by Israeli billionaire Lev Leviev, has gold tiles and a retractable cover that turns the entire area into a ballroom. The Gellert Thermal Baths in Budapest, Hungary, are the oldest and most famous public bathhouses in operation today. They are fed by over 100 hot mineral springs.
The Zodiac is a circular pool deep beneath India's Umaid Bhawan Palace. It's in a room covered with gold tiles, and the bottom of the pool is made of mosaics that depict the signs of the Zodiac. Another of the world's most luxurious hotel pools is at the Sarojin Resort near Phuket, Thailand. It offers floating pavilions complete with floating massage tables.
The Kitchukov family of Gilbert, Arizona, owns the most expensive private pool in America, with a construction cost of $1 billion. It has fountains, waterfalls and a waterslide that is 15 feet (4.5 meters) tall [source: Walsh].
The pool at the City of Stars resort complex, in the works in Sharm el Sheikh, Egypt, is slated to be over .6 miles (one kilometer) larger than the world's current biggest pool. The builders, Crystal Lagoons, are also planning a 30-acre (12-hectare) pool in Soma Bay, Egypt [source: Construction Week Online].