Mark Zuckerberg reveals what 5000-square-foot 'Doomsday shelter' underneath $270,000,000 house is actually used for

Facebook owner Mark Zuckerberg has revealed what the so-called 'underground bunker' built beneath his $270,000,000 house in Hawaii is actually used for.

If you had a net worth of $184.6 billion, what would you spend it on?

I'd have to go for a mansion with a pool, a private chef and a vacation home, but I guess it couldn't hurt to have some sort of survival bunker in place too - just in case.

A lot of people suspected that's what Zuckerberg was up to when news of his 'shelter' in Hawaii emerged a couple of years ago, with an investigative report from Wired revealing that the expensive home was built on a 1,400-acre compound and was shrouded in secrecy.

According to planning documents seen by Wired, the property would include 'a 5,000-square-foot underground shelter [and] have its own energy and food supplies'.

Mark Zuckerberg has multiple properties (Aurelien Meunier/Getty Images)

Two years on, Zuckerberg alluded to this underground space when he sat down for an interview with Theo Von, who admitted that if he had the means, he'd have both a 'chopper' and an 'underground tunnel'.

The Facebook founder responded to admit he did have an underground tunnel, though he suggested stories about the space had got out of hand.

"There's this whole meme about how people are saying I built this like bunker underground," he said.

Zuckerberg then went on to reveal what the vast space was actually used for, and it's not quite as exciting as you might have hoped.

Zuckerberg insisted the shelter isn't as exciting as it sounds (David Ramos/Getty Images)

He explained: "It's like more of underground storage situation."

Zuckerberg added that the tunnel led from one building to another, but he distanced himself from Von's idea of 'hiding a bit of dope' in the secret space, saying: "You and I differ there."

The billionaire's Hawaii home is located on the island of Kauai, on a quiet stretch of ranchland between the more touristy spots of Kapaa and Hanalei.

Plans viewed by Wired revealed that the compound is made up of more than a dozen buildings, with at least 30 bedrooms and 30 bathrooms, as well as offices, conference rooms and an industrial-sized kitchen.

There are a series off treehouses connected by rope bridges, and a spa-like area filled with a gym, pools, sauna, hot tub, cold plunge, and tennis court.

It might sound like the kind of space you'd never need to leave once you got there, but Zuckerberg is actually known to spend the bulk of his time at his home in Palo Alto, California.