The Beltane Fire Festival is an annual festival marking the arrival of Summer held on the top of Calton Hill. It started as a free event and now attracts 12,000 people to the pantheistic procession with a huge cast of characters.
But what is going on and what does the ceremony mean?
The festival performance begins on the Acropolis after dark, where the May Queen, symbolic of the Earth, reveals herself from within her winter retreat.
She and the White Women warriors greet the four points of the compass to begin the ritual.
The Green Man, her consort for the year and symbolic of summer growth, presents himself and the procession starts off around the hill, guided by the druidic Blue Men and driven by pounding drum rhythms. The procession passes first through a fire arch. It then visits sites representing the four elements : Air, Earth, Water and Fire - inhabited by sylphs, goblins, nymphs and sprites respectively.
Each group of performers joins onto the end of the procession until it numbers more than a hundred strong.
As the May Queen's court rounds the final corner to complete the circuit of the hill, they are ambushed by the mischievous Red Men, and their Beastie Drummers, who attempt to disrupt the procession with lewd and lascivious behaviour.
The warriors' focus proves too strong, however, and the Blue Men break up the standoff to allow the court to move to the stage.
At this stage, the movement of the procession changes from counterclockwise to clockwise, indicating the changing season.
The May Queen and the court spin on and around the stage and the tension mounts.
The Green Man, overcome with expectancy, makes a grab for the May Queen but is dragged down by the four handmaidens, symbolically killed, stripped of his winter garb, and revived as a fresh green sapling.
After an ecstatic dance of life and vigour, the Green Man and May Queen are married and summer can begin.
The procession moves off to the bonfire, which is lit by the May Queen. A twin fire is created from the same spark by the Red Men, the Fire crew and the Beastie Drummers on the stage and the onlookers are then invited to pass between them and so be purified by the fire.
Everyone is invited to place an offering on the fire to burn out the old. With the main ritual achieved, the court retires to the May Queen's bower to rest and be entertained by the elemental performers.
The last ritual event of the night takes place when the Red Men approach the bower and symbolically seduce the White Women into dance. Chaos and order are fused and the unity of all elements is complete.