Floating building?

I often glance out my window as I sit at my desk. I often see ships passing as they travel the North sea routes.

Big boats, small boats, ferries, tankers, container ships.... but the variety of cruise liners sizes and shapes is quite amazing. Sometimes they are very, very large and very, very odd, like floating block of flats on their sides.

Can't say I fancy a cruise but lots of people seem to love them and Orkney benefits greatly from their visits.