For a while, it seemed like Pink Floyd might vanish into the background of prog rock history—a band weighed down by psychedelia and half-finished ideas. After Syd Barrett’s departure in 1968, the band spent the next few years releasing albums that, while occasionally brilliant, lacked the focus and purpose of their stunning debut, The Piper at the Gates of Dawn.

There were glimmers of greatness in that in-between period—especially the sprawling masterpiece “Echoes” from 1971’s Meddle—but it wasn’t until their eighth album that everything finally aligned.

While touring in 1972, Pink Floyd began shaping new material during soundchecks and live performances. What emerged was a bold leap forward: The Dark Side of the Moon. The album took almost a year to complete and marked a profound shift in the band’s approach—an intricate mix of sonic experimentation, studio wizardry, and lyrical depth that captured themes of madness, greed, mortality, and time. It would become one of the best-selling albums in history, with more than 45 million copies sold.

Roger Waters, the band’s primary lyricist, wanted a strong closing statement for the album—something that would bring all of its themes full circle. That idea became “Eclipse.” Built on lyrics that echo the album’s opening track “Breathe,” the song flows directly from “Brain Damage,” closing the record in a powerful, almost spiritual crescendo.

Guitarist David Gilmour recalled the challenge of arranging such a minimal structure into something emotionally impactful. “I remember working hard on making it build and adding harmonies that join in as you go through the song,” he told Rolling Stone. “Because there’s nothing to it—there’s no chorus, there’s no middle eight, there’s just a straight list. So, every four lines we’ll do something different.”

The arrangement is deceptively simple, yet profoundly effective. “Eclipse” builds steadily, with each phrase adding layers of instrumentation and harmony, culminating in a dramatic climax before returning to the soft heartbeat that opened the album. This circular structure—later echoed on The Wall—gives the album a sense of completion, both thematically and musically.

Lyrically, Waters avoided cryptic metaphors. Instead, he delivered a direct meditation on life’s dualities—the light and dark, the good and the bad, the choice between reaching for meaning or succumbing to the void. “I don’t see it as a riddle,” Waters explained in Bricks in the Wall. “The album uses the sun and the moon as symbols; the life force as opposed to the death force. All the good things in life are there for us to grasp, but something dark in our nature stops us.”

That emotional clarity is part of what set Pink Floyd apart. While other prog bands were diving headfirst into fantasy concepts and excessive instrumental displays, Floyd channeled those same ambitions into music that cut straight to the human condition.

“Eclipse” isn’t just an ending—it’s the mirror held up to the rest of the record. It’s what made The Dark Side of the Moon more than just a prog rock milestone. It made it eternal.