Recessed Lighting - Hidden Lighting

I am trying to find out what the term used to describe a type of lighting so I can do some research on it. I first saw it in palm springs in a rather luxurious home. I walked in and never saw any lightbulbs but the lighting was sufficient to read a news paper from. In the bathroom there was soft lighting illuminating from under the sink basin and from the overhead, but no bulbs were visible. Some people mentioned that it was rope lighting, but it doesn't seem like the type of lighting that would go in a multi-million dollar home.

Please can you help?

I am in the process of decorating my room and will be putting up a picture rail. We have wall lights, but is it possible to have a thin strip of light that is hidden at the back of the picture rail so that just a soft light appears outf "nowhere"?

Many thanks
Jayne