Sunken bathtubs was the trendy thing back in the '70's and '80's. I remember seeing it in a home that I viewed at an open house. It really isn't as neat as one would think. Stepping down into a tub is awkward. I've been told that the easiest way to get into a sunken tub is to sit on the floor, put your legs into the tub, and then scoot over into it.