Google cofounder Larry Page built a man cave in his secret startup's office

It must be nice to be a billionaire.

Alphabet CEO Larry Page, for example, has discreetly poured part of his wealth into two secret startups, Zee.Aero and Kitty Hawk, which are dedicated to building flying cars, reports Bloomberg.

But making a classic science-fiction dream reality isn't even the coolest part. Apparently, Page turned the entire second floor of Zee.Aero's headquarters into a "man cave worthy of a billionaire" - complete with a bedroom, climbing wall, and an actual rocket engine, courtesy of Tesla and SpaceX CEO Elon Musk.

From Bloomberg:

Page initially restricted the Zee.Aero crew to the first floor, retaining the second floor for a man cave worthy of a multibillionaire: bedroom, bathroom, expensive paintings, a treadmill-like climbing wall, and one of SpaceX's first rocket engines - a gift from his pal Musk. As part of the secrecy, Zee.Aero employees didn't refer to Page by name; he was known as GUS, the guy upstairs.

Zee.Aero employees got a few nice perks too, such as catered lunches, including at one point, $900 of catered barbecue.

But Page didn't keep his secret office crash pad for long. Apparently, Zee.Aero expanded so quickly that eventually it needed the second floor for more engineers - it now employs 150 people - so Page had to move out his expensive paintings, workout gear, and collectibles.

But it's not like he can't afford to build a new man cave. Anyone who can spend at least $100 million on the idea of a flying car, which may not ever come to fruition, has more than a little money to burn.