1. MUSA Underwater Museum — Cancun, Mexico
2. Jacob's Well — Wimberly, Texas
3. The Neptune Memorial Reef — Key Biscayne, Fla.
Not far from Miami, this memorial was artistically based off the Lost Empire of Atlantis. According to the memorial's website, "Those who choose cremation for final needs may opt for their remains to be deployed to the reef, creating life after life." The Department of Environmental Resource Management has witnessed marine life around the area grow from zero into the thousands because of the memorial.
4. Green Lake — Tragoess, Austria
Green Lake is no ordinary park. Once a year, this park is submerged in water after all the snow on the Karst Mountains melts. It has become a popular attraction for scuba divers all over the world.
5. Underwater Waterfall — Mauritius Island
The underwater waterfall on the coast of Mauritius is nothing but an optical illusion. It's created by sand falling down the coastal shelf into the depths of the deep blue sea. The best way to observe this majestical illusion is from above on a plane or helicopter.
6. Whale Diving — Kingdom of Tonga
When you visit Tonga you'll have the opportunity to swim with humpback whales and feel what it's like to be part of marine life. Whale Discoveries will help you learn everything there is to know about the complex submarine mammal.
7. Azure Window — Maltese Island of Gozo
This travel destination is popular for cliff diving off the Azure Window and scuba diving inside the Blue Hole cave. Inside the 262-foot tunnel, scuba divers have found incredible marine life such as fire worms and octopi.
8. Weeki Wachee Springs — Spring Hill, Fla.
If you don't believe in mermaids then you have to go to this mermaid city. For 60 years the park has put on mermaid shows in an underwater theater, including productions of The Little Mermaid.
9. Cenote Angelita — Tulum, Mexico
Cenote Angelita is best known for its underwater river: yes, a river that runs underwater. According to scuba diver Alice Yoo, this river is created by a layer of hydrogen sulfate that separates the salt water and the freshwater and creates a cloud-like moving stream.
11. Homestead Crater - Midway, Utah
"Over 10,000 years in the making,” Homestead Crater is a hot spot for scuba diving, snorkeling, paddleboard yoga classes, and other water-related activities. If you don't want to get wet, you can also take land-based tours that explain the history of the crater.
12. Underwater Bar & Club — Maldives
Subsix bar is the world's first underwater bar and club. Now you can show off to your friends on social media that you party with marine life in the depths of the Indian Ocean.
14. Atlantis — Palm Islands, Dubai
Atlantis is the underwater empire you want to stay in on your next vacation. Certain parts of the hotel — like the lobby — are underwater, so walking through the halls will feel like you're submerged in an aquarium at all times.
15. Great Blue Hole — Belize
According to researchers, this is the biggest blue hole — underwater cave or sinkhole — in the world. It's more than 984 feet across and it's estimated to be 410 feet deep. This site is very popular amongst divers who like to explore the geological formations of the coral reefs.