The cube looms on the horizon like a Bond villain's lair and boasts enough security to make even the most paranoid evil mastermind feel safe.

Three high-tensile fences surround the mysterious monolith amid rows of floodlights and a checkpoint manned by armed guards.

There are fingerprint scanners, heavy steel doors and endless cameras to prevent anyone from getting to the treasure held within.

There are no signs revealing what's inside but the imposing exterior suggests something very valuable. Perhaps national secrets, or a confidential lab experiment.

For once, the reality is just as exciting: the cube is brimming with billions of dollars in cold hard cash. This is the National Banknote Site, Australia's Fort Knox.

On a recent tour, The Age was given a close-up look at the extraordinary levels of security and the way cash is dispensed on the first steps of its journey into our wallets and purses.

The man taking us inside is Michael Andersen. As the RBA's head of note issue, he has overseen the first major overhaul of Australia's banknotes since polymer bills replaced paper cash in 1992.

The intention of the vault's design, he says, was to create as many safeguard layers as possible. Breaching one in a heist might be possible but getting through all of them would not.

"It's like an onion and no one knows them all," he says.

Once inside, we move through a series of steel doors, which are activated with a fingerprint scanner or passcode. Only one can be opened at any point and they close automatically with a heavy click.

"It's like Maxwell Smart," says Mr Andersen, "and if these doors closed on you, you'd really know about it."

To read the complete article, see:
Inside the mysterious vault that has locals scratching their heads(https://www.theage.com.au/national/victoria/inside-the-mysterious-vault-that-has-locals-scratching-their-heads-20180503-p4zd6t.html)