La Villa dei misteri
This Villa is located just outside the city walls. On it is the most famous Pompeian wall-painting. It contains a room (that is called The Initiation Chamber) which is decorated with very beautiful but strange scenes. Initiations took place here and they marked a transition from childhood to adulthood. There is an opening between the first and last scenes of the fresco that leads into the chamber.
La Villa dei misteri pompei - Pompei