A mystical island cave in Scotland and a sunken limestone pool hidden in the desert of Oman, these are amongst the world's top-secret swimming holes.

A mystical island cave in Scotland and a sunken limestone pool hidden in the desert of Oman, these are amongst the world's top-secret swimming holes.

A mystical island cave in Scotland and a sunken limestone pool hidden in the desert of Oman, these are amongst the world's top-secret swimming holes.

A mystical island cave in Scotland and a sunken limestone pool hidden in the desert of Oman, these are amongst the world's top-secret swimming holes.

From an underwater caving adventure in Brazil to a breathtaking 230-foot rain forest waterfall, these are the world's top-secret swimming holes!

From an underwater caving adventure in Brazil to a breathtaking 230-foot rain forest waterfall, these are the world's top-secret swimming holes!

From an underwater caving adventure in Brazil to a breathtaking 230-foot rain forest waterfall, these are the world's top-secret swimming holes!

From an underwater caving adventure in Brazil to a breathtaking 230-foot rain forest waterfall, these are the world's top-secret swimming holes!

From an underwater caving adventure in Brazil to a breathtaking 230-foot rain forest waterfall, these are the world's top-secret swimming holes!

From a perch on the edge of the world's largest waterfall to an underground river in Mexico, these are some of the world's top-secret swimming holes.

From a perch on the edge of the world's largest waterfall to an underground river in Mexico, these are some of the world's top-secret swimming holes.

From a perch on the edge of the world's largest waterfall to an underground river in Mexico, these are some of the world's top-secret swimming holes.

From a perch on the edge of the world's largest waterfall to an underground river in Mexico, these are some of the world's top-secret swimming holes.

From a perch on the edge of the world's largest waterfall to an underground river in Mexico, these are some of the world's top-secret swimming holes.

Adventure seekers take an excursion across an iceberg-laden lake in Iceland. And, a couple explores an island's pink sands off the coast of the Bahamas. Episode 12 season 2.

Adventure seekers take an excursion across an iceberg-laden lake in Iceland. And, a couple explores an island's pink sands off the coast of the Bahamas. Episode 12 season 2.

From diving with tiger sharks in the Bahamas to sandboarding massive dunes in Australia, thrill seekers check out the world's most action-packed beaches. Episode 11 season 2.

From diving with tiger sharks in the Bahamas to sandboarding massive dunes in Australia, thrill seekers check out the world's most action-packed beaches. Episode 11 season 2.

Adventure seekers take an excursion across an iceberg-laden lake in Iceland. And, a couple explores an island's pink sands off the coast of the Bahamas. Episode 12 season 2.

From Easter Island's mysterious beach, to an ATV tour in Iceland and swimming with wild pigs in the Bahamas, adventurers enjoy top swimming holes. Episode 10 season 2.

From Easter Island's mysterious beach, to an ATV tour in Iceland and swimming with wild pigs in the Bahamas, adventurers enjoy top swimming holes. Episode 10 season 2.

Adventure seekers take an excursion across an iceberg-laden lake in Iceland. And, a couple explores an island's pink sands off the coast of the Bahamas. Episode 12 season 2.

From diving with tiger sharks in the Bahamas to sandboarding massive dunes in Australia, thrill seekers check out the world's most action-packed beaches. Episode 11 season 2.

At the world's top-secret swimming holes, there's Australia's Champagne Pools, Jet blading in Singapore, and an underground dip in a Samoan sinkhole. Episode 9 season 2.

At the world's top-secret swimming holes, there's Australia's Champagne Pools, Jet blading in Singapore, and an underground dip in a Samoan sinkhole. Episode 9 season 2.

From diving with tiger sharks in the Bahamas to sandboarding massive dunes in Australia, thrill seekers check out the world's most action-packed beaches. Episode 11 season 2.

From Easter Island's mysterious beach, to an ATV tour in Iceland and swimming with wild pigs in the Bahamas, adventurers enjoy top swimming holes. Episode 10 season 2.

At the world's most stunning swimming holes, there's sandboarding in South Africa's biggest dunes and swimming with wild, endangered penguins. Episode 8 season 2.

At the world's most stunning swimming holes, there's sandboarding in South Africa's biggest dunes and swimming with wild, endangered penguins. Episode 8 season 2.

From Easter Island's mysterious beach, to an ATV tour in Iceland and swimming with wild pigs in the Bahamas, adventurers enjoy top swimming holes. Episode 10 season 2.

At the world's top-secret swimming holes, there's Australia's Champagne Pools, Jet blading in Singapore, and an underground dip in a Samoan sinkhole. Episode 9 season 2.

Secret swimming holes include a cliff diving spot in the Dominican Republic, a hot spring in Utah, and hidden pools on Easter Island. Episode 7 season 2.

Secret swimming holes include a cliff diving spot in the Dominican Republic, a hot spring in Utah, and hidden pools on Easter Island. Episode 7 season 2.

At the world's top-secret swimming holes, there's Australia's Champagne Pools, Jet blading in Singapore, and an underground dip in a Samoan sinkhole. Episode 9 season 2.

At the world's most stunning swimming holes, there's sandboarding in South Africa's biggest dunes and swimming with wild, endangered penguins. Episode 8 season 2.

From a canyon full of a black water to an exotic animal safari leading to a secret beach, these are some of the world's top-secret swimming holes. Episode 6 season 2.

From a canyon full of a black water to an exotic animal safari leading to a secret beach, these are some of the world's top-secret swimming holes. Episode 6 season 2.

At the world's most stunning swimming holes, there's sandboarding in South Africa's biggest dunes and swimming with wild, endangered penguins. Episode 8 season 2.

Secret swimming holes include a cliff diving spot in the Dominican Republic, a hot spring in Utah, and hidden pools on Easter Island. Episode 7 season 2.

From swimming with sharks in Belize to kitesurfing in the Caribbean, thrill seekers explore the world's most top-secret swimming holes! Episode 5 season 2.

From swimming with sharks in Belize to kitesurfing in the Caribbean, thrill seekers explore the world's most top-secret swimming holes! Episode 5 season 2.

Secret swimming holes include a cliff diving spot in the Dominican Republic, a hot spring in Utah, and hidden pools on Easter Island. Episode 7 season 2.

From a canyon full of a black water to an exotic animal safari leading to a secret beach, these are some of the world's top-secret swimming holes. Episode 6 season 2.

From an underground lagoon on the Hawaiian island of Oahu to a desert canyon oasis in Oman, explorers uncover the world's best-kept swimming hole secrets. Episode 4 season 2.

From an underground lagoon on the Hawaiian island of Oahu to a desert canyon oasis in Oman, explorers uncover the world's best-kept swimming hole secrets. Episode 4 season 2.

From a canyon full of a black water to an exotic animal safari leading to a secret beach, these are some of the world's top-secret swimming holes. Episode 6 season 2.

From swimming with sharks in Belize to kitesurfing in the Caribbean, thrill seekers explore the world's most top-secret swimming holes! Episode 5 season 2.

A mystical island cave in Scotland and a sunken limestone pool hidden in the desert of Oman, these are amongst the world's top-secret swimming holes. Episode 3 season 2.

A mystical island cave in Scotland and a sunken limestone pool hidden in the desert of Oman, these are amongst the world's top-secret swimming holes. Episode 3 season 2.

From swimming with sharks in Belize to kitesurfing in the Caribbean, thrill seekers explore the world's most top-secret swimming holes! Episode 5 season 2.