This sublime image has turned up on a number of blogs including Royal Quiet Deluxe and Lucky Charm (I was alerted to it by Drumz of the South twitter feed). The photo was taken by Weegee - as the photographer Arthur Fellig (1899–1968) was known - and was featured in an exhibition at the International Center of Photography a few years ago. Weegee was a Jewish immigrant to the US from Ukraine, and is best known for his portrayal of life in New York. So I am guessing that this 1956 photo, entitled 'Couple in Voodoo Trance', was taken in the States rather than in the Haiti homeland of Voodoo (or Vodou).
What is striking is the calm dignity of these participants - who could be dancers anywhere - quite at odds with the racist caricature of Vodou as some blood-crazed evil cult. Such caricatures have sadly been getting quite an airing in the aftermath of the earthquake in Haiti, most notably from right wing US Christian fundamentalist nutjobs like Pat Robertson, who blamed the earthquake on a pact between Haitians and the devil. Clean Living in Difficult Circumstances is among those who have taken these views to task.