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Figure 8 Pools, Australia - The fascinating result of two sinkholes merging, the Figure 8 Pools at Sydney Royal National Park in New South Wales are one of the region's most fascinating—and inviting—natural wonders.

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Giola Laggon, Greece - Welcome to the mirror-like Giola Lagoon, located near Astris on Thassos island. This is one of the Mediterranean's most attractive natural swimming pools.

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Horseshoe Lake, Canada - Secluded Horseshoe Lake, situated in Alberta's Jasper National Park, is a horseshoe-shaped lake just a 1.5-km (1-mi) hike from the trail-head. It's nestled among high cliffs and thick forest and is one of Canada's most scenic stretches of water.

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Boat Harbour Beach, Australia - A ten-minute drive from Wynyard, a rural town on the Australian island state of Tasmania, Boat Harbour Beach boasts white sand, clear-blue waters, and lots of rock pools to explore.

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Yucatán, Mexico - Prepare to be spellbound as you slide into the turquoise waters of Cenote Ik Kil. Float under a shaft of daylight as you take a shower with the sun.

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Arizona, USA - One of many outstanding natural wonders found in America's landmark Grand Canyon, Havasu Falls, set with the Havasupai tribal lands, requires a short hike from Supai to reach, and it's worth every step.

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Treyarnon rock pool, England - This scenic rock pool is found in the UK's North Cornwall region. Dip your toes in it or snorkel in its ice blue water.

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Samoa, Pacific Islands - To-Sua Ocean Trench in Lotofaga is the lushest, greenest sinkhole on the planet. The photograph says it all. Enjoy.

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Vanuatu, Pacific Islands - Wow! How blue is this? The Nanda Blue Hole, sunk near Natawa, is a freshwater gem, and absolutely breathtaking in appearance.  

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Texas, USA - Historic Hamilton Pool Preserve appears as if sculptured out the surrounding limestone rock. Note that visiting the preserve and swimming must be booked in advance.

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Babinda, Australia - Check out Queensland's natural rock pools, smoothed down over the centuries by the elements. The area holds deep significance to local Aboriginal Australians. One restricted area called the "Devil's Pool" is believed to be cursed. Enter at your own risk.

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Whalers Way, Australia - South Australia's Whalers Way is a bit of a trek, but the secret swimming hole, only accessible via a short scramble, is definitely worth it. You must drop by Port Lincoln Visitor Centre to get directions.

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The Grotto, Canada - The Grotto can be found in Bruce Peninsula National Park, Ontario. Some call it Cyprus Lake Grotto, others call it Georgian Bay Grotto. But whatever you choose to name it, it's one of the best hidden swimming holes in the country.

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Yucatán Peninsula, Mexico - Dzibilchaltun is a Maya archaeological site. But it's also known for the fabulously family-friendly cenote, or sinkhole.

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Crammel Linn, England - Look for this delightful water feature along the River Irthing, in Northumberland. It's the county's biggest waterfall.

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Ormiston Gorge, Australia - West MacDonnell National Park near Alice Springs in Northern Territory is home to Ormiston Gorge, a local treasure. Blessed with cool waterholes, it's best to bring a tube with you to float on.

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Horseshoe Falls, Wales - Located in Denbighshire, this is a horseshoe-shaped waterfall that cascades into a series of inviting plunge pools.

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Devil's Pool, Zambia -

If you have a head for heights you'll have no problem peering over the edge of the mighty Victoria Falls while bathing in the Devil's Pool. (Photo: Flickr/CC BY-SA 2.0)

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Maria Island, Australia - With no vehicles and no shops, Maria Island, located off the Tasmanian coast, is a no-stress paradise. It's a wonderful place to enjoy walking, cycling, snorkeling and, or course, swimming.

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Elora Quarry, Canada - Found a short two-hour drive from Toronto, this two-acre Ontario quarry features breathtaking turquoise water and sheer cliffs topping out at 12 m (40 ft).

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Mindanao Island, Philippines - The cascading Tinago Falls, located in between the town of Linamon and Iligan City, releases a wonderfully fine spray as it tumbles into the Agus river.

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Muscat, Oman - Bimmah Sinkhole is exactly what you need to escape the desert heat. And the best thing? It's not a mirage!

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Cascade Ponds, Canada - This idyllic family-friendly swimming hole in Alberta's picturesque Banff National Park features a small beach, shallow water, access to picnic tables, and nearby walking trails.

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The Blue Hole, Malta - Located on the Maltese island of Gozo, this natural wonder is what it says on the label—an blue-colored plunge pool of considerable depth. It's better for scuba divers than swimmers. (Photo: Flickr/CC BY-NC 2.0)

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Lake Malawi, Malawi, Mozambique, Tanzania - This African great lake borders three countries, so it's up you to decide where to take a dip in its warm waters. (Photo: Flickr/CC BY-NC-ND 2.0)

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Luang Prabang, Laos - Swimming in the three-leveled Kuang Si Falls is akin to splashing around in a series of giant oyster shells. Lots of fun!

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Mindanao Island, Philippines - The Hinatuan Enchanted River is a magically clear deep spring river that rises in the jungle to flow slowly into the sea. 

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Yucatán Peninsula, Mexico - Cenote Dos Ojos ("Two Eyes" in Spanish) is a flooded cave system found north of Tulum. A favorite cavern diving site, the less ambitious will enjoy snorkeling its crystal clear waters.

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Glenbrittle, Scotland - Travel to the Isle of Skye to find the enchanting Fairy Pools, noted for their vibrant blue and green hues. This is Scotland, so expect cold water...and a real thrill.

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Bryher Island, England -

Bryher is one of the islands that belongs to the Isles of Scilly, moored just off the Cornish coast. It's a great weekend getaway destination where swimming, boating, or kayaking options abound.

See also: Nazaré: the biggest waves in the world

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