The World's 10 Strangest Pools

These aren't your backyard swimming holes. The strangest pools in the world will take you for a swim by the terraced gardens of Bali, in blood-red water in Turkey or in a 3000-foot monstrosity built on the Chilean coast.

Intercontinental Hotel Where: Hong Kong The Intercontinental Hotel in Hong Kong has lavish amenities and the skyline to back it up. And the cherry on top is a set of three pools that sit atop its third-floor spa deck, overlooking Victoria Harbor. With the three pools set to different temperatures—cold, warm and hot—visitors can choose the water that's just right as they enjoy the closeup view of the Hong Kong skyline.

Blue Lagoon Geothermal Spa Where: Grindavik, Iceland Blue Lagoon is one of the most famous spots on an island known for its gorgeous and mystical geothermal features. The pool is fed by superheated water vented from the ground near a lava flow, and the lagoon is renewed every two days by a nearby geothermal plant through a combination of natural and artificial filtering. Water is heated naturally beneath the earth's surface and takes in minerals on its way to the lagoon. The water, which stays at about 100 degrees Fahrenheit, is rich in minerals like silica and sulphur, and some people claim it has healing powers for skin diseases like psoriasis.

San Alfonso Del Mar Where: Chile The largest swimming pool in the world is more than 3000 feet long, with a deep end that descends 115 feet. Sitting seaside at a resort in Chile, the pool required nearly five years to build and cost $1.6 billion. It has an annual maintenance fee of $3.2 million. Containing more than 66 million gallons of water, it dwarfs the second biggest pool in the world (the Orthlieb in Morocco with a mere 9.5 million gallons). The pool keeps a constant flow of fresh seawater into the pool and old water back out to the sea, using a filtration system to desalinate the seawater before it goes into the pool and clean the pool water before it goes back to the ocean.

Golden Nugget Where: Las Vegas, Nevada The Golden Nugget casino's pool may take top honors as the scariest of the strange pools; it gives you the feeling of swimming with the sharks, without actually swimming next to them. The pool wraps around a giant tank for marine life that cost nearly $30 million to complete, and includes a three-story waterslide that runs through the middle of the tank. Don't worry: There's clear glass between you and the sharks.

Rangali Island Where: Maldives Jutting out into the Indian Ocean from a tiny island in the Maldives, this luxurious pool belonging to the Conrad Maldives Resort and Spa is in the class known an "infinity pools," which are designed to dissolve the edges of the pool and make you feel like you're floating atop the ocean itself.

Ubud Hanging Gardens Where: Bali, Indonesia At the Ubud Hanging Gardens in Bali, swimmers get two exotic choices: Overlook the valley from the swimming pool on high, or get into the thick of things in the lower pool among the terraced gardens. Either way, it's clear that you're going to have a swimming experience unlike any other you've had before.

Where: India When the Umaid Bhawan Palace of Northern India was finished in 1943, it was the largest private residence in the world with 347 rooms in all. Later, part of the palace was commissioned into a lavish hotel where guests can live like royalty. For those guests, the palace offers access to the underground Zodiac Pool. The pool, housed deep beneath the palace itself, is covered in gold tiles with the twelve signs of the Zodiac painted on the pool bottom, giving an eerie vibe to an otherwise serene experience.

SkyPark At The Marina Bay Sands Where: Singapore Singapore's SkyPark at the Marina Bay Sands offers an infinity pool with a first-class view—55 stories up. Perched atop the three towers of the world's most expensive hotel, the water seamlessly flows over the edge, into a catchment and back into the pool. The pool itself touches all three buildings and is longer than the Eiffel Tower laid on its side.

Nemo 33 Where: Brussels, Belgium Formerly the world's deepest pool (until San Alfonso Del Mar stole that title in 2007), Nemo 33 remains the deepest indoor pool at 108 ft. Using highly filtered spring water at 96 degrees Fahrenheit, the pool is home to diving instruction, recreational use and film production. Divers can explore the system of underwater caves, and because Nemo 33 stays a constant warm temperature, they don't even need wetsuits.

Where: Victoria Falls, Southern Africa Atop Victoria Falls in southern Africa, one of the largest waterfalls in the world, is one of the scariest pools in the world. In the natural formation called Devil's Pool, swimmers can look over the falls in relative safety as thousands of gallons of water from the Zambezi River plunge 128 meters into the gorge. At the edge of the pool there is a rock wall that prevents the river from pulling swimmers over the edge. But jumping in is still a harrowing experience for first-time visitors, who can't see the protective wall from the shore.