Build your own Bat Cave

I noticed this yesterday and was a little perplexed. I mean seriously what are you going to do with a huge underground estate besides build a bat cave. You could equip it with all the latest gadgets and race cars around the miles of underground roads or you could do what no one would expect and open it as a new development to ease the over crowding in Europe. Actually it could be used for a whole bunch of stuff, not least of all as a stockpile for your nuclear weapons but whatever you did it had better be fun. Actually I could think of better ways to spend that amount of money such as buying your own island with a recording studio or something.