The world's oceans are much more than giant fish ponds – discover life-sized sculptures, ancient caves, ruins and more on your next dive, says Graihagh Jackson
As the world's only submerged gypsum crystal cave, Ordinskaya is a haven for underwater explorers. It's not for the faint-hearted though – the entrance is through a 5x2m hole in the ground, guided by a 50m long ladder.
With over 50km² of submerged caves, Ordinskaya is the second-most extensive underwater network in Eurasia. You'll discover a maze of intricate tunnels, crystal clear underground lakes and unearthly landscapes. The caves are yet to be completely explored, so who knows what other wonders are waiting to be discovered?
Considered the Mecca of cave diving, Ordinskaya is open only to certified cave divers. There is a dive centre nearby in Perm offering a choice of three Technical Diving International (TDI) courses for those who want to extend their certification to include cave diving.
Over coral and colourful fish? Then head to the azure waters of the National Marine Park of Cancún and dive amongst British artist Jason de Claire Taylor's extraordinary Silent Evolution installation instead.
The installation comprises of 403 life-size sculptures, modelled on real people, sprawled across the ocean floor. Reef life has already started developing on the figures, with a sometimes chilling, sometimes comical effect.
Cancun's National Park is renowned for housing some of the world's most beautiful reefs and hosts 750,000 visitors each year. The sculptures' location promotes the recovery of the surrounding natural reefs, while housing marine life. Eventually, it will host a complex reef structure itself.
Silfra is a freshwater fissure where two tectonic plates are gradually moving away from each other forming a fracture in the earth's surface. Here the continents of Europe and America face off against each other, and if your arm span is wide enough you can touch the two continents at once.
There are other freshwater rifts, of course, but divers claim Silfra in Iceland's Þingvallavatn National Park is the most beautiful. Exceeding 100m in depth and with visibility over 100m, the site has three main sections to the dive: the Silfra Hall, which leads to a 45m deep cave system; the 100m long fracture of Silfra Cathedral surrounded by lava walls; and the bizarrely-blue waters of the Silfra Lagoon.
Research has revealed a bizarre underwater structure off the coast of Japan's Yonaguni-jima island is an incredible 10,000 years old. Geologists argue the structure is nothing more than a rock formation, eroded by currents over thousands of years. Archaeologists claim that they are submerged constructions, built by the ancient Mu civilisation.
So, Asia's answer to the lost city of Atlantis or merely a peculiar rock formation? Either way, the underwater 'ruins' is one of the region's most quixotic dives.
Once they've burrowed through up to three metres of sea ice, divers in McMurdo Sound may be surprised to discover an underwater world as bright and colourful as the tropics.
The sea-floor here is rich in brilliantly-coloured creatures. Divers can admire bright-yellow cactus sponges, star fish, sea urchin and jellyfish. The spectacular visibility of 300m ensures you won't miss the underwater cliffs and ocean valleys, or (if you're lucky) the occasional Emperor penguin.
Cruises to the continent depart from Ushuaia, Argentina. Diving is best from September to February when the waters are ever-so-slightly warmer.
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