One warm evening in May 1997, in the grounds of a country house just off the M1, thousands watched Kraftwerk, the enigmatic Mensch-Maschine, successfully evolve. Their appearance at the dance music one-dayer Tribal Gathering was the group's first ever festival set. To be there was to witness Kraftwerk in the context of the dance music they had inspired and were inspired by. The tent was filled with a healthy mix of electro-warriors, club night regulars and curious, slightly square undergraduates who loved Underworld and Leftfield as much as Pulp and Suede. The Trans-Europe was opened by Two Lone Swordsmen on the final leg of their eight-hour sound-system set. By 11pm, the tent was a mass of tight, whooping waves made up of every demographic: most revellers by now felt accepted in the festival's mix of glammed-up ravers, trance hedonists and hoodie-wearing ordinary Joes. Then as a robotic voice cut through; "Meine Damen und Herren," it began... Before Tribal Gathering, Kraftwerk played theatres and tribute shows. After it, they became festival fixtures. For almost all attendees it felt precious to be there at that pivotal moment, at both a peculiar homecoming and something of an annunciation.