It was supposed to be the adventure of a lifetime for Tom and Eileen Lonergan.
But the American couple's dream dive in the Great Barrier Reef ended in tragedy when their tour group forgot them in the shark infested waters - a story so haunting that it would go on to inspire Chris Kentis' thriller film Open Water.
It was in January 1998 when they boarded the Outer Edge and set off on their scuba diving trip, where they spent hours underwater, gliding through the breathtaking valleys of the St Crispin Reef.
But when they resurfaced, their dive boat was gone.
Left behind by their tour boat in the middle of the ocean, Tom and Eileen found themselves stranded, but even worse, no one on board had realised that the married couple had not returned form their scuba dive until two days later.
By the time rescuers scoured the diving spot, Tom, 33, and Eileen, 28, were nowhere to be found.
The pair had married in their home town of Baton Rouge, Louisiana, nine years prior to their trip after meeting at Louisiana State University.
Seeking adventure, they joined the US Peace Corps in 1995 and were assigned work as teachers in the poverty-stricken Pacific islands of Tuvalu and Fiji.
On a fateful day in January 1998, Tom and Eileen Lonergan (pictured) boarded a scuba dive boat to explore an area of the Great Barrier Reef off the Australian coast
Their story inspired Chris Kentis' thriller film Open Water
In January 1998, they left for Australia - the last stop on their great adventure before returning to the US.
On Sunday, January 25, they took the hour-long coach journey from Cairns to Port Douglas, where they boarded the Outer Edge for the voyage to St Crispin Reef, 38 miles offshore.
They enjoyed two 40-minute dives, and later prepared for a third dive at a site known as Fish City because of its abundance of underwater life.
There were dozens of sharks around the reef at the time, according to local fisherman Mick Bird, who was a few miles away that day. 'Every time we threw a line, we'd pull in a shark - they should rename that place Shark City,' he said.
Around 3pm, when everyone should have been back on board, Geoffrey 'Jack' Nairn, the former skipper of the Outer Edge, asked crew member George Pyrohiw to do a headcount - a vital practice that should have been conducted with the greatest care.
Twenty-six people should have been on board. But as Pyrohiw was counting, two divers jumped into the water to take last-minute photos. Pyrohiw told Nairn he'd counted only 24.
According to Pyrohiw, the skipper then said: 'And two in the water makes 26.' Mr Nairn disputes this, but in any case, it seems that the two passengers who jumped overboard were counted twice.
After the Outer Edge docked at Port Douglas late that afternoon and the passengers disembarked, the crew noticed that two dive bags remained on board.
The couple spent more than half an hour diving underwater. But when they resurfaced, their dive boat was nowhere to be seen
They were simply moved to another part of the boat; the crew assumed the owners would ring once they realised they'd left them behind.
In addition to the bags, an inventory showed the boat was missing two air tanks and two weightbelts - but no one queried this.
Norm Stigant, the driver whose job was to take passengers back to their hotels, told his boss that the Lonergans had not shown up for the ride, but was urged not to worry and eventually left without them.
Night closed in. Tom and Eileen were still out there, and no one knew.
The following day, the Outer Edge returned to St Crispin Reef with new passengers, its crew still unaware of their fatal mistake.
Divers descended to marvel at the fish - and within a short time had spotted and retrieved two weight-belts on the seabed. The find provoked no action or comment.
Another day went by, and the Outer Edge took out a new boatload of passengers and then returned to Port Douglas for the second time since the Lonergans' fateful dive.
But there were still the unclaimed dive bags on the boat, and at last skipper Jack Nairn decided to open them.
On Sunday, January 25, the Lonergans took the hour-long coach journey from Cairns to Port Douglas, where they boarded the Outer Edge for the voyage to St Crispin Reef, 38 miles offshore
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He found a wallet and ID documents, and a shirt that Tom Lonergan had been wearing on the day of the dive trip. Realising something was terribly wrong, he reached for the phone.
It was now 51 hours since the Lonergans had last been seen. They had not returned to their hotel, and police soon discovered their credit cards had not been used. A huge air and sea search was mounted, but no trace of the couple was found.
Ten days later, Tom's buoyancy jacket, with his name neatly printed on the pocket, was found 50 miles north of St Crispin Reef.
A green and grey wetsuit, believed to be Eileen's, was later washed up. It had jagged tears in the buttocks area, presumed to have been caused by a shark. Her buoyancy jacket, hood, fins and air tank eventually washed ashore, too.
Six months later, the ocean yielded its most sickening legacy. In July, a fisherman 90 miles north of St Crispin Reef hauled in a slate that divers use to write notes to each other underwater.
On it was a faded cry for help which read: 'Monday, January 26, 1998. 8am. To anyone who can help us. We have been abandoned here by the Outer Edge. Please help us or we will die. Tom and Eileen Lonergan.'
Experts have been unable to agree if the find is genuine or a cruel hoax.
The bodies of the adventure-loving couple have never been found - just a mangled wetsuit and some of their equipment.
Various theories as to what happened after the boat left the reef were put forward during the investigation and the coroner's inquest.
Investigators discovered their personal diaries in their hostel room in Cairns, in Queensland on Australia's east coast, which revealed several disturbing entries.
'I feel as though my life is complete and I'm ready to die,' Tom had written six months before him and Eileen vanished.
'As far as I can tell, from here my life can only get worse. It has peaked and it's all downhill from here until my funeral.'
One of Eileen's last diary entries, just 16 days before the pair disappeared, hinted at personal troubles.
'Tom hopes to die a quick and fairly [painless] death and he hopes it happens soon. Tom's not suicidal, but he's got a death wish that could lead him to what he desires, and I could get caught in that.
Detective Sergeant Paul Priest said at the inquest a few months after the couple's disappearance that he had initially found the diaries discovered in their hostel room 'chillingly bizarre' and 'prophetic', but he had eventually dismissed them as the private musings of an introspective couple.
The Lonergans' tragic story went on to inspire thriller film Open Water, which tells the story of a couple who become stranded miles from shore in shark-filled waters when the crew of their scuba diving boat accidentally leaves them behind.
NSW grandmother Suzanne Rees, 80, is being remembered as a keen bushwalker and gardener by her family following her death over the weekend
A similar tragedy would go on to repeat itself more than two decades later when an Australian grandmother was found dead on a remote island after she was accidentally left behind by a cruise ship.
Suzanne Rees was on the second day of a $80,000 cruise circumnavigating Australia when she disembarked on the remote Lizard Island last Saturday.
The 80-year-old had planned to hike with other passengers on the main lookout, but according to Suzanne's daughter Katherine Rees, the grandmother fell ill during the organised hill climb and was asked to travel back down the mountain, unescorted.
'Then the ship left, apparently without doing a passenger count. At some stage in that sequence, or shortly after, Mum died, alone,' she told The Australian.
It is understood that Suzanne was not reported missing until about 6pm on Saturday evening when she failed to arrive for dinner, five hours after she was allegedly left behind.
Her body was spotted the next day by a search helicopter crew about 50 metres off the hiking trail to the look out, with reports suggesting she may have fallen from a cliff or slope.
News of Suzanne's death has shocked the world, with questions raised over how an elderly woman could have been left on an island alone to die.