3D photo merge/montage app?

Hi,

I was recently on holiday and while in a beautiful old building saw a man taking photos on his iPad 2, the app he was using then merged them/created a montage which replicated the inside of this building in 3D, it looked incredible and gave a real sense of the experience and I would really like to find out what the app was!!! I should have asked him then and there but I doubt we would have spoken the same language, and I was a coward! Though this didn't stop me from standing behind him for two minutes whilst he did it...

Much fruitless google searching has occured but I still haven't found the right one.

If anyone has any ideas that would be fantastic!

Thanks very much, Miriam