>> they would ceremoniously enter the chambers adorned, lamp lit. one of the most sacred spots in the ancient city. >> and you see the thermal water coming here. >> i see it. yeah. people came here without eating, without drinking, and all the gas gave a change of perception in the minds. >> they go into this altered state? >> yes. altered state to have a dream, and after this dream came the healing. it's not possible to heal without the mind. they are strictly connected. >> the ancients practiced the psychedelic right as late as the 12th century. they figured out something