When Osama Bin Laden was finally tracked down, it turned out he was living in what is considered to be a mansion by Pakistan standards, but it was pretty much a run-down compound. It's nothing compared to the high-tech bunker system the Pentagon thought was his hiding place. The Times of London even made up a graphic of what it might look like:
Calling it "comic villain's super fortress", Gizmodo writes:
The absurd graphic, birthed from rumors stacked upon rumors originating with a former Russian soldier, placed Osama inside a bunker that would make Lex Luthor blush. The thing, tunneled as deep as the World Trade Center was built high, looks like a super duper hideaway I would have drawn up with magic marker as an 8-year-old: secret exits, booby traps, missile launcher caches, all deep enough in a mountainside to withstand bombardment and massive enough to hold 1,000 men. So, yes, bad enough that the press' imagination ran wild with visions of Osama's MTV Cribs-worthy terror mansion.
The idea was given legitimacy by then-Secretary of Defense Donald Rumsfeld on "Meet the Press" in December 2001:
Tim Russert: The Times of London did a graphic, which I want to put on the screen for you and our viewers. This is it. This is a fortress. This is very much a complex, multi-tiered, bedrooms and offices on the top, as you can see, secret exits on the side and on the bottom, cut deep to avoid thermal detection so when our planes fly to try to determine if any human beings are in there, it's built so deeply down and embedded in the mountain and the rock it's hard to detect. And over here, valleys guarded, as you can see, by some Taliban soldiers. A ventilation system to allow people to breathe and to carry on. An arms and ammunition depot. And you can see here the exits leading into it and the entrances large enough to drive trucks and cars and even tanks. And its own hydroelectric power to help keep lights on, even computer systems and telephone systems. It's a very sophisticated operation.
Rumsfeld: Oh, you bet. This is serious business. And there's not one of those. There are many of those. And they have been used very effectively. And I might add, Afghanistan is not the only country that has gone underground. Any number of countries have gone underground. The tunneling equipment that exists today is very powerful. It's dual use. It's available across the globe. And people have recognized the advantages of using underground protection for themselves.
As we now know, these fortresses do not exist, in the real world, anyway.