Latecomers to the Krautrock party, Circles created a manifesto of frenzied inertia in the late 1980s, swimming in the same gene pool as Cluster and Popol Vuh. Ambient music for the end of time does not get any more authentic than this. The Structures album is a time capsule unlocked, containing previously unreleased recordings from the years 1985 to 1989. Music which meshes the extremes of "end of time foreboding" and "drifting lightness" to beguiling effect. Music which succeeds in sounding more contemporary now that it did when it was made. Its time has come. Electronic keyboards and guitars are the dominant sound sources. One can hear a Korg Trident, a much-prized analogue synthesizer, noted for its string and brass section ". for the warm, deep layers and harmonies in the upper ranges and bass", Mike remembers. They also used a monophone analogue synthesizer, the Moog Source, a classic of space age industrial design. Considered by some to be the most beautiful synth ever built.