The hypnotic sound of the drums and singing stirs the group of people dressed in white into a slow, rhythmic shuffle around the room.
Bemused by the unfamiliar ritual we turn to ask our guide, Luis, a question, only to see him drop to his knees and shake as if overcome by an epileptic fit.
A woman rushes over to steady him as his eyes roll into the back of his head and he convulses uncontrollably.
Although Luis had warned us this might happen, it was still a shock to see and we stand awkwardly to one side as the helper takes off his shoes and glasses, dabs the sweat from his brow and puts a cup of cold water to his lips.
Within a few minutes Luis has regained consciousness and, although still slightly dazed and exhausted from the experience, is able to tell us more.
We have just witnessed one of the “trances” that are a regular happening during ceremonies of the African-Brazilian religion of Candomblé.
Candomblé’s beginnings date back to when the first Africans were forcibly shipped to the coastal city of Salvador, in the north-east state of Bahia.
Such was the fear created of the slaves’ spiritual beliefs among the conquistador landowners, that those practising it were persecuted and driven to hold ceremonies in secret.
Today, private places of worship remain dotted around the city and as night falls we are driven 45 minutes from the cobblestoned old centre, the Pelourinho, to the back streets of a nondescript neighbourhood.
Once there, we are welcomed with a smile and offered a seat in the large bright room, in which the simple white walls have been adorned with masks and where fragrant green leaves have been scattered on the floor.
“You are very lucky, tonight is an initiation ceremony,” whispers Luis, as out of a sideroom emerge two young women. Their hair and eyebrows have been shaved off and colourful dots of paint dabbed all over their skin.
The folds of their voluminous starched petticoats brush against our legs as they are led past, their eyes closed and a solemn expression on their faces.
They appear to be totally lost in the repetitive percussion and other members of the community sporadically fall into a trance and crumple on the floor.
Luis tells us that the Candomblés believe there are a number of different spirit Gods, or Orixás, representing the earth and its elements.
The Orixás possess different characteristics, transferred to followers in the same way that astrologers believe unique zodiac sign traits are bestowed upon individuals.
“A trance happens when your Orixá takes control of your body,” explains Luis. “Not everyone is born with this ability, but those who aren’t can take on other roles such as playing percussion, preparing food for the ceremonies or aiding those who are entranced.”
He goes on to tell us about his first entrancement: “I was 24. It was a very frightening experience, I felt dizzy and my blood pressure dropped.
“Then the spirit got in me and I felt like half-me and half-spirit. You don’t see it, but you feel it. Mine is the Orixá of communication, but there are many Orixás.”
According to Luis, entrancement can last for a few minutes, an hour or many days.
“Special ritual ‘tests’ are conducted when people join the community to ensure that they are not faking their entrancement,” he adds.
After the opening part of the ceremony concludes, the two women leave the room, to later return with blood trickling down their heads, beneath a few white feathers.
Luis notices our bewilderment and interjects: “As part of the initiation a dove is sacrificed. The dove is white, which represents purity. White is the presence of all colour, white is open, whereas black represents a lack of all colour and is banned.”
Earlier, Phil had been asked to swap his dark shorts for a pair of light trousers in keeping with the custom.
Luis is keen to stress that Candomblé should not be mistaken for voodoo or black magic, insisting: “It is an entirely different and independent form of worship.”
His voice is drowned out by an entranced man across the room who is bent over and uttering a deep, throaty roar – a characteristic of the warrior Orixá, Ogum.
Throughout the ceremony the persistent drum beat is accompanied by chant-like singing – Luis tells us this is borne of the way slaves used to sing to distract themselves from the arduous labour they had to undertake.
After four hours it is drawing near to 11pm and the ceremony is only half-way through. Traditional snacks and drinks are periodically offered to onlookers and to participants who take regular breaks in the fresh air.
We leave behind the vivid sights and enchanting drums of this historic faith that appears to be as vibrant today as it was four centuries ago.