'Ghost Adventures' Star Zak Bagans Buys Underground Las Vegas Cold War Bunker House

It sounds like Zak Bagans has another ghost adventure brewing ... this time in the Vegas bunker house he just bought, TMZ has learned.

The "Ghost Adventures" star dropped $4.5 mil on the 16,000-square-foot property, which boasts painted skies, fake landscaping, a pool, and lighting designed to replicate the different hours of the day -- the sprawling home is known as the "Underground Mansion" and has a Cold War luxury bunker hidden nearly three stories beneath an ordinary home.

Apparently, when Zak did a walk-through of the impressive estate, he learned about the bunker's dark history, which was so spooky that some staff refused to go down there alone.

MrBeast filmed there and called it “one of the most expensive and bizarre bunkers on the planet,” and Imagine Dragons shot the video for “Monday” inside the bunker.

TMZ has learned that Bagans plans to make it into a museum, opening it to the public for the first time. We're told he also wants to make an original documentary feature.

He says ... "Once I was actually in the process of buying it, I was shocked by how many different mysteries are tied to this house, things I don’t wanna reveal just yet."

Zak says he plans to preserve the house and its history, so he can "dig deeper into the mysteries."