Answer
"666", released in 1972, is indeed a classic psychedelic rock album by Greek musician Vangelis. Departing from his earlier works, it exhibits a fusion of rock, electronic, and progressive elements, characterized by hypnotic synthesizer runs and spacey sound effects, blending with distorted guitar riffs and powerful drumming. The album invites listeners on a captivating journey through its sonic landscapes, reflecting the experimental spirit of the era.