Off the coast of Belize lies an underwater sinkhole so deep that scientists aren't sure how deep it goes.
In Chetumal Bay, the Taam ja' sinkhole, a 'blue hole', has proven a challenge for researchers trying to measure its depth, the Telegraph reports.
Using sonar to map the hole, they found that Taam ya' is approximately 274 meters deep – but these measurements can be inaccurate, due to differences in temperature and salinity in each layer of water.
Divers were sent into the hole, approximately 30 meters deep, and discovered that the walls of the hole were soft and uneven, before turning into harder rock.
After anchoring a boat above the opening of the hole, a research team lowered a massive cable, 500 meters long, into the hole, but it was not long enough to reach the bottom.
The researchers noted that the instrument could have been pushed sideways by currents and thrown out of the measurements, but the mystery remains: how deep is Taam ya'?
Despite repeated attempts to measure the hole with long cables, there has been no definitive measurement of its depth.
For years, the Sansha Yongle blue hole, in the South China Sea, was believed to be the deepest blue hole in the ocean.
If scientists can measure the depth of Taam ja', it could replace the Sansha Yongle Hole as the deepest measured sinkhole in the ocean.
It is believed that Taam ya' may have a network of underwater caves and tunnels, making its measurement even more difficult.
Earlier this year, scientists were able to extract a sediment core from the bottom of the seafloor that provided a 5,700-year-old archive of storms.
Sediment layers showed that over the past six millennia, on average, between four and 16 tropical storms pass over the hole per 100 years.
The Great Blue Hole is located about 60 miles off the coast of Belize City and is part of the Belize Barrier Reef, a UNESCO World Heritage Site.
It was formed at the end of the last Ice Age, when rising sea waters flooded a series of giant caves.
It is thought that the caves were formed around 153,000 years ago and were completely submerged around 15,000 years ago.
The hole is populated by several species of sharks, including Caribbean reef sharks, hammerhead sharks, bull sharks and blacktip sharks. /Telegraph/
