By definition anarchism advocates a stateless society, so I guess I can't be talking about an Anarchist State or Country so I will just use state of anarchy (with no negative connotation).
In any place that has been exposed and converted to an organised, hierarchical society, has there ever been a successful return or conversion to anarchy? By successful I mean a state of anarchy that persisted for at least a few generations and where the inhabitants were able to live decently in relative security. So this would exclude little 'social experiments' that didn't last.
In the absence of one or more successful anarchies, what are/were the most promising ones?
EDIT: As pointed out in the comments, any answer to this question may be subjective and depend on the interpretation of stateless.
I won't consider implicit agreements to be a form of government (like being nice to people hoping they'll be nice to you in return).
Obeying special people like elders and religious figures would be considered a form of government, unless there is no punishment for going against their opinions and they are merely looked up to as being worthy of attention.
Also I would like to point out that I am talking about a conscious educated decision to move towards an anarchist society. As such tribes who have arguably been in that state since the dawn of man or societies that have ended up in that state as a result of war or other breakdown of their society do not count.