Best Place to Convert into an Extreme Home

If you have seen Extreme Homes then you have seen that people have converted some strange places, such as lighthouses, banks, old barns, and such into new residences. What kind of place would you like to live in, or convert into a home, if you can live in any strange or esoteric place. Use your imagination here! Also, if you could imagine stuff still in the place, like if you actually lived in a working WalMart-that would be awesome.