This luxurious pool is the most expensive pool in the world. It is constructed by Crystal Lagoons and is worth $5.5 billion. The Citystars pool occupies a massive 23.9 acres making it the largest pool in the world. Pool experts report that this pool is likely to be the most famous and crowded pool in the whole world.

The pool is part of the Citystars resort complex and surrounded by more than 30,000 condo and hotel rooms. Residents and guests can swim or even sail a boat in this pool. It incorporates seawater that uses a non-chlorine sanitation system. Make a point of traveling to Egypt to visit this pool in the future.

Location: Sharm El Sheikh, Egypt

Cost: $5.5 Billion

Located in the resort town of Algarrobo on Chile's southern coast, the San Alfonso del Mar has changed the way the world looks at swimming pools. That's because this pool is large enough to sail a boat in, and if you swim its entire length, you'd cover 8/10ths of a mile (1.3 km). Measuring more than 20 acres (8 hectares), the San Alfonso is 6,000 times larger than your average hotel pool and was named the largest pool in the world by the Guinness Book of World Records in 2008.

The pool took five years to build and cost nearly $2 billion USD (about $1.1 trillion Chilean pesos). Thus, it is among the most expensive pools in the world. Developers used an innovative salt-water filtering technology created by Crystal Lagoons to purify more than 66 million gallons (2.5 million liters) of ocean water to fill the pool.

It opened in 2007 as part of the San Alfonso del Mar resort, which is home to thousands of apartments, condominiums and hotel rooms. While the pool isn't open to the public, all resort guests and residents have unlimited access.

Location: Algarrobo, Valparaíso, Chile

Cost: $2 Billion

On days when it's too cold to swim at the beach, guests at the Sheraton Seagaia Resort in Miyazaki, Japan, can head to the resort's indoor pool. Known as the "Ocean Dome", Seagaia is home to the largest indoor pool in the world. The pool is nearly 1,000 feet (300 meters) long and 328 feet (100 meters) wide, and it's covered by a retractable roof that lets the sun shine in on warmer days. Several times a day, the pool is cleared to allow surfers to catch a wave, and an artificial volcano erupts every 15 minutes. Ocean Dome's beach is made from crushed quartz, and there's even a separate children's pool and waterslide area.

Seagaia Ocean Dome cost a staggering $2 billion (200 billion yen) and opened in 1993. It has been closed down several times since then due to changes in ownership or financial difficulties. In October 2007, the Ocean Dome was closed indefinitely as the resort began a major renovation and restructuring and was demolished 10 years later after the hotel had received major renovations which did not include the dome.

Location: Miyazaki, Japan

Cost: $2 Billion

In 2008, Israeli billionaire Lev Leviev and his family moved into the most expensive private home ever built in the United Kingdom. Located in North London, the house cost $68 million USD (35 million British pounds) to build, and is home to one of the world's most expensive pools.

Leviev's indoor swimming pool is lined with gold tiles and has a full spa and sauna. When it's time to host a party, the pool has a retractable cover that transforms the area into an opulent ballroom. Unfortunately, this pool is open only to friends and family.

Location: London, United Kingdom

Cost: $68 Million

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.

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.

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.

Location: San Simeon, California, USA

Cost: $10 Million

Located in Budapest, Hungary, the Gellert Thermal Baths are among the world's oldest and most famous public bathhouses still in operation. Built between 1912 and 1918, the baths are a well-preserved example of the Art Nouveau design popular during that period. The Baths feature multiple pools measuring more than 7,500 square feet (700 square meters), including an outdoor wave pool, children's pool, and luxurious Roman baths.

The pools in Gellert are fed by more than 100 hot mineral springs that are believed by many to have natural healing properties. Visitors will find classic design features including fine marble, mosaic tile, and priceless works of art. On warmer days, the building's retractable roof is opened to allow swimmers to enjoy the sun. Best of all the pools are open to the public, allowing anyone to enjoy a luxurious swim for a nominal fee.

Location: Budapest, Hungary

Cost: $3.6 Million

It’s the deepest scuba diving indoor pool in the world. Located in Brussels, Nemo 33 has a maximum depth of 133 ft. It’s filled with 2,787,878 million liters of highly filtered, non chlorinated spring water and maintains a constant water temperature of 30 degrees Celsius. It took seven years to construct and has plenty of underwater tunnels and rooms for visitors to explore.

Nemo opened to the public in 2004 and is primarily used by scuba divers and film crews looking to film underwater scenes. If you’re a certified diver you can dive in the world’s deepest indoor pool by paying a nominal fee. The pool also offers diving classes to non divers.

Location: Brussels, Belgium

Cost: $3 Million

The town of Gilbert, Ariz., is home to America's most expensive and luxurious private pool. Kichukov Family Pool was built by Red Rock Contractors and is at least 10 times larger than the average backyard pool. It took 5 months to build at a cost of $1 million and is equipped with waterfalls, fountains and a 15-foot (4.5-meter) waterslide. When the sun goes down, the area is lit by an elaborate lighting system that the family can use while enjoying the 15-person hot tub or full bar. Rich landscaping surrounds the pool, along with a putting green and skateboard bowl.

One of the most impressive features of the pool is its state-of-the-art control system. Using a ScreenLogic interface, the family can control the pool's operations from anywhere in the world with the touch of a button. The ScreenLogic system allows users to remotely adjust the pool's temperature, change the color of the lighting, or even warm up the Jacuzzi. Best of all, this program can be accessed from any Internet connection, or using the company's new iPhone app.

Location: Arizona, USA

Cost: $1 Million

Thailand's Sarojin Resort is home to one of the most luxurious hotel pools in the world. Located near the Phuket resort area, The Sarojin has been named Asia's most luxurious small hotel for several years in a row by the World Travel Awards. Set to open in December 2004, the multi-million dollar resort was destroyed by the Asian tsunami and had to be completely rebuilt. It opened just eight months later and helped draw visitors back to the region.

The Sarojin's infinity pool measures 269 square feet (25 square meters) and overlooks the Indian Ocean. Guests can lounge amid lush tropical landscaping, or relax on floating pavilions within the pool itself. For the ultimate in luxury, schedule a massage at one of the pool's floating massage tables and soak up the spectacular ocean views.

Location: Phuket, Thailand

Cost: $1 Million

The Umaid Bhawan Palace in India is part hotel, part royal residence. When it was completed in 1943, it was the world's largest home, and required the work of more than 3,500 builders. Construction of the palace cost more than $225,000 USD (11 million Indian rupees) and took 15 years to complete.

One of the palace's most spectacular features is its indoor pool, which is located deep underground in the heart of the building. Known as the "Zodiac," the pool is circular and themed in a classic Art Deco style. The bottom of the pool is covered with tile mosaics depicting the signs of the Zodiac, while the walls and ceilings in the room are covered with thousands of one-inch (25.4-millimeter) tiles covered in gold. Today, hotel guests can swim in the pool along with members of India's royal family, who still live in their own private wing of the palace.

Location: Jodhpur, Rajasthan, India

Cost: $225,000