No, it's not the Illuminati, it is Caodaism. Founded in 1926 in Vietnam (then, of course, Indochine) by Ngo Van Chieu, it is an eclectic fusion of Buddhism, Confucianism and Taoism, with a sprinkling of Christianity thrown in. Then Ngo Van Chieu stopped and meditated for a while - something was not right with his new religion. It was not... wacky enough. Bright colours... check. Weird saints... hey, what about weird saints? And how about worshipping a radical rationalist French writer? How about making Victor Hugo one of our principal saints? Huh, how about that?
Fast forward to today, we have the Holy Seat of Cao Đài in Tây Ninh
Seemed to me that it was mainly designed for Tourism - a convenient gallery encircles the cathedral, full with tourists snapping pictures of the ceremony which takes place four times a day:
Here it pays of to have a long lens:
I think these guys are Caodaistic (?) laypersons, as far as I know only priests take part in the ceremony itself. Either that, or they are the Holy Seat's assassin squad.