rf - simplest FM radio receiver?

As per this building simple radio it is the simplest AM radio receiver.

obviously this is very poor AM receiver.(but it was working for someone in comment)

I'm wondering what will happen when this receiver is very near to FM radios transmitter? will it work?

if no, How will the simplest FM radio receiver look like?

Answer

For a totally passive FM set you can use something like a resonant circuit that is tuned somewhat off the carrier frequency so variations in carrier frequency result in changes in output voltage from the detector at the baseband frequency. This is called 'slope detection'.

For example, from this website:

This should also work to pick up AM signals.

An even simpler circuit is presented here.