There may be a forgotten time capsule sitting still, quiet and empty eight metres below the bustling surface where Degraves Street meets Flinders Street in the heart of Melbourne.

Around fifteen years ago, two colleagues made their way down a few sets of stairs through their shop’s storeroom and came across a breathtaking sight.

Through the dim light they made out an intricately carved wooden ticket booth with panelled glass windows, sitting in the centre of a space with elaborate art deco tiling, red brick walls and what appeared to be a platform.

They saw two tracks running alongside it, leading off into dark tunnels on either side.

This is the scene Dominic Kaukas came across when he was managing a Mitchell’s store in 1999 – something he describes as a light rail platform – and whatever it is he saw that day has played on his mind ever since.

He almost stumbled across his words in his hurry to describe the details of what he saw, with a nervous quiver in his voice.

“It was so stunning that it was emblazoned onto my memory,” he said.

“I thought, this is a lot of work for something that doesn’t exist.”

He’s right, it doesn’t – at least not officially.

The space isn’t recorded in historical documents or even in the public memory, but in the context of the mystifying world of Melbourne’s underground, this doesn’t mean as much as you might think.

The vast world that exists underneath the rapidly changing and ever growing city is one almost completely unknown to many of its residents, with hundreds of kilometres of storm water drains and sewerage pipes forming a labyrinth of infrastructure.

There’s much more to it though, with countless cases of confirmed historical tunnels and basements, many dating back to the nineteenth century, when cool basements were used to transport and store goods.

There are well-documented tunnels and air raid bunkers under the Royal Melbourne Hospital, which were built in the 1930s and used during the Second World War to house around 35,000 soldiers wounded in the Pacific region.

In the CBD, tunnels under the major banks and department stores like Myer were used to transport gold and cash safely, and a recently uncovered tunnel in Richmond is believed to have been used by notorious gangster Joseph “Squizzy” Taylor to escape police raids.

Historian Meyer Eidelson runs tours of subterranean Melbourne, and has heard endless stories, whispered rumours and sinister theories about many of the confirmed and unconfirmed sites.

 “The tunnels are always a source of mystery. They’re scary places,” he said.

“People have an endless fascination with them – maybe it’s because of the mining history of Melbourne, but there seem to be more tunnel mysteries than you can poke a stick at.”

As for what Kaukas saw down there that day, Eidelson was quite open to the idea, and came up with a theory about its connection to Campbell Arcade, which runs under Flinders Street and was built for the 1956 Olympic Games.

“The short answer is yes. There is a complex down there,” he said.

“Whether it’s an art deco rail system with tracks, well that’s an interesting thought. I wouldn’t say that it’s not true.”

For Melbourne historians and writers, many of the tales of from the nineteenth century are well-worn yarns by now, written into books and articles that look at the city’s past.

The most contentious and magnetic aspect of the whole underground Melbourne mystery surrounds the U.S. military’s involvement in Melbourne during the Second World War from 1942-3.

This is where characters like Mark Rawson come into the picture.

Part-time criminal lawyer, part-time chaser-down-of-mysteries, Rawson is an enigma of a man with a booming baritone voice and some real charisma.

In between donning a tie and suit for his court appearances, he’s spent most of his spare time for the past few decades digging for the truth.

The physical manifestation of the thought and work that Rawson has put into following leads is a bulging manila folder full of photos, letters, hand-scrawled notes and newspaper clippings.

“As a criminal lawyer, you’re sort of taught to research stuff and follow the facts and not to rely wholly and solely on what you’re told, but to actually investigate it a bit more thoroughly,” he said.

“The more we dug into it, the less information there was, and that was very strange. Because it should be on record.”

As Kaukas searched for answers on his 1999 sighting, he came across Rawson and they’ve maintained contact over the years.

Rawson is the go-to person for anyone who’s seen or heard something strange about Melbourne, and he’s always got a handful of leads on the horizon.

He’s sure that the U.S. military heavily expanded some of the existing tunnels, and built many of their own, and believes there’s been a serious cover up.

“If the records disappear, then we’ve lost information about infrastructure that was put in years ago,” he said.

“You’ve got skyscrapers being built on sites that may have a tunnel under them, and you’ve got to remember that none of these tunnels will last forever – eventually they will all collapse.”

During the early 2000s Mark and a group of enthusiasts were granted permission by the Darebin Council to excavate a tunnel leading from Merri Creek, one such mystery, and they spent most weekends for about six years hauling wheelbarrows as they excavated the site.

Eventually the council decided that they didn’t want the group there, and the dig came to a halt.

The secretive, yet widely recognised group Cave Clan may know more about how Melbourne is mapped out under the surface than anyone, simply because they have actually spent decades exploring the city through the storm water drains.

The movement started in the 80s when a group of three young friends helped to kick off the urban exploration trend through their own adventures, and has since grown to include thousands of explorers both officially and unofficially affiliated with the original group.

A longtime member of the group now living interstate laughed off some the speculation and hearsay that is thrown around by those looking into the tunnels.

“You just go there,” he said.

“I know it’s easier said than done, but then again, it’s not really.”

The Cave Clan member was more doubtful about Kaukas’ find, citing the fact that the Clan has such a thorough knowledge of this area that the existence of an undiscovered rail tunnel would be surprising, but not out of the question.

A number of years ago, Kaukas and Rawson went back and visited his old work site.

They were dismayed to find the spot completely changed, with a new development covering the area.

Kaukas believes that the access point he used to reach the space has been built over.

These days he carries a camera with him wherever he goes.

“It’s my word against somebody else’s, but I swear on whatever you want, I’ve actually seen it,” he said.

In cities from Las Vegas and New York to London, the worlds that lie beneath have captured the imagination of the populations living above the ground.

Storm water tunnels in Las Vegas house large portions of the city’s homeless population, and entire communities and groups have developed a distinct lifestyle down there.

In London, there are up to forty tube stations that were closed down over the years, and they’ve long been a point of fascination for urban explorers, photographers and historians.

The public’s fascination with underground worlds ebbs and flows, but as time rushes forward there are always people behind the scenes, retelling the stories and keeping the history alive.

A 1946 article published in the Argus weekend magazine entitled, ‘There’s a Strange World Beneath Melbourne,’ is eerily relevant to conversations that are taking place now.

It describes an underground tour taken of a system of walkway tunnels right underneath the grid of Melbourne CBD, complete with electric lights and street names corresponding to the intersections above painted on makeshift signs.

Sixty years later the elusive underground still drives a need to find out more in all sorts of people – from young people seeking adventure and freedom, to a criminal lawyer who has literally shovelled tonnes of dirt over the years in search of some solid answers.

Eidelson tries his best to find the facts between the myths as he leads a mixture of tourists and locals through the city, helping to quell the insatiable curiosity people have about what lies beneath the place that has been home to millions over the years.

“I was running rooftop tours and of course people were always asking, ‘what about the underground?’” he said.

 “Paris has the catacombs, in London you can go into the Roman streets underground, so what about Melbourne?”