Nineteen-sixty-six was one of the most interesting years in the history of pop music. Right alongside the groundbreaking singles and albums by the Beach Boys, the Beatles and the Mothers of Invention, were the Rolling Stones, right in the middle of things.

In April, the band released its classic Aftermath LP, signaling a giant leap forward. The single that was issued at the same time showed that evolution in full bloom. "Paint It, Black" wasn't just another song by just another rock group; it was an explosion of ideas presented in one neat three-minute package.

As the song's haunting guitar riff kicks in, giving way to Charlie Watts' pounding drums, it becomes obvious that the Stones weren't resting on the laurels of their recent No. 1 hit, "(I Can't Get No) Satisfaction." In 1965, the Beatles introduced the sitar to pop music; now it was the Stones' turn to run with it. Guitarist Brian Jones, who had mastered many instruments during his time with the group, follows the main riff, as well as the melody, on sitar, creating a distinct sound that shot out of radios during the spring and summer of 1966. It's a fully integrated instrument within the context of the song, playing off Keith Richards' guitar perfectly.

"Paint It, Black" is psychedelia with a backbone and a driving beat. "It was a different style to everything I'd done before," Richards told Rolling Stone. "Maybe it was the Jew in me. It's more to me like 'Hava Nagila' or some gypsy lick. Maybe I picked it up from my granddad." (The comma in the song's title was not originally there, by the way. The record company added it, but nobody is really sure why.)

Mick Jagger delivers one of his finest vocal performances, with dark, intriguing lyrics to match the song's vibe. Add Watts' powerhouse drumming and Bill Wyman's contributions on bass and Hammond organ, and you've got one of the most engaging records of a year filled with them.

With today's instant-gratification market, it's hard to wrap our heads around just how revolutionary "Paint It, Black" sounded on Top 40 radio 50 years ago. It not only sounded nothing like anything else being played, it was hugely popular, hitting No. 1 across the world.

Since its debut on May 13, 1966, "Paint It, Black" has been covered by artists spanning the Animals to U2. It's a popular choice in movies and TV shows too. The Stones also apparently still like it a lot. It's a regular addition to their live performances to this day.

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