Like many others, he was keen to enjoy the untamed Northern Territory outback before the unbearable heat of the wet season "build up" arrived.

A fit and well prepared 67-year-old, he set up his caravan and campsite as he had many times before, making himself comfortable, chatting to his neighbours.

The Queenslander wasn't one to waste time and set off for a walk on the Leliyn Track to the top rock pools, not a long way but a steep climb all the same.

He wasn't one to take the bush for granted, Mr Rosenberg knew the perils of the bush well, especially when travelling solo.

He wore protective clothing, a khaki hat and sturdy hiking boots, of the top-of-the-range Salomon variety.

When travelling anywhere in unfamiliar bush he carried a small day pack and a walking pole.

Although mobile phone coverage in the Edith remains virtually non-existent, it was his routine to also carry his Samsung Edge mobile phone and a Samsung Galaxy tablet.

After stretching out on the loop track, he returned to camp for a Saturday night refresher, nothing amiss.

The following day, the Sunday, he kitted up again, with all his bush gear, and made sure his camp site was in order and ready for his return, and set off again on the Leliyn walk, it was about mid-morning.

He tackled the popular eight kilometre return walk from Edith to Sweetwater Pool. He told his new camp neighbours as much and he was later seen returning from the direction of the much-photographed pool.

Then he vanished.

Disappeared into thin air.

He has never been seen again.

Despite an exhaustive search by emergency services by air, by land, and even by water, not a trace of Mr Rosenberg could be found.

Not his person, not his gear, none of it.

It never has.

Was he taken by a crocodile, was he trapped by a snag underneath the cold, deep water of the plunge pool at the falls, was he the victim of a kidnapper?

Not forgetting that Paddy Moriarty, the Irishman from Larrimah just a few hours down the Stuart Highway, had also vanished in mysterious circumstances less than seven months before.

Moriarty, aged 70, and his dog had sat down for their evening meal together in the tiny town just before Christmas in 2017, and have never been seen again.

Foul play is still the most likely explanation for Moriarty's disappearance, what had befallen Mr Rosenberg?

The tracks are well marked, his family insist he was not only fit but healthy for his age.

Had he veered off course to explore some place in this extensive wilderness and become injured?

The NT is not over-imbued with rescue gear but police threw everything at the search, the failed Moriarty sweep gave them recent experience.

Helicopters flew ever widening circles for days, experienced park rangers walked the bush, even police divers were brought in to scour the depths of the tourist-famous clear rock pools.

The main plunge pool is up to 28-metres deep.

Nothing.

There were hundreds of people at Edith that weekend, many thousands have visited to enjoy the long dry season since, still not a trace.

Today police say the search for Mr Rosenberg remains ongoing.

The investigation remains open.

But the physical search has ended.

The best hope today is that one of the many people still enjoying one of the tourist hot spots of the Top End will come across some evidence of his final resting place.

The walking pole, clothing, perhaps his electronic gear.

The public, locals and tourists are the best hope now.

A family in Queensland who still desperately miss their father, their grandfather, would dearly love the closure.

And to take Mr Rosenberg back home.

Anyone with information on his whereabouts is urged to contact police on 131444 or Crime Stoppers on 1800 333 000.

Katherine Times