Time has a marvelous ability to render the absurd familiar. Mankind can harvest vast energy from the basic stuff of matter, using means that only people with considerable higher education can even describe accurately. But nobody’s taken aback by this fact because, welp, they’ve been doing that shit since your grandpa’s time. Humans can fly! We cured smallpox! You can talk to anyone on the planet instantaneously! These facts are insane when you think about them, but nobody does because we’re used to them. (My favorite Louis C.K. bit deals with this phenomenon, but I digress.)

In the same way, Pink Floyd — one of the most popular musical groups of all time — has been normalized by their ubiquity. Their record sales figures alone boggle the mind. According to Wikipedia, they’ve sold roughly 250 million albums.

The human brain tends to gloss over numbers of that size when they’re delivered without context, so here’s some. In 1990, there were just under 250 million people living in the United States of America. Pink Floyd has effectively sold an album to every single one of those people. That puts them ahead of Celine Dion, AC/DC, the Rolling Stones, and ABBA, among others. Only the Beatles, Elvis, Michael Jackson, Led Zeppelin, Madonna, and Elton John have done better.  And that figure doesn’t include all of the people who’ve pirated their albums, or who never bought their albums but have heard their music on the radio for decades, or who’ve lived with family members and spouses who played Pink Floyd in their homes, and so on. Their cultural reach is epically, imperially huge.

And that reach does not end with their album and merchandise sales, which continue to pile up almost 20 years after their demise. Pink Floyd’s songs have been covered, referenced, and parodied into oblivion. Planetarium laser shows set to their music are so popular that they’ve become a stoner cliché. The poster of six naked women with Floyd album covers painted on their backs is a dorm-room staple, rivaling Dalí’s The Persistence of Memory and the Scarface film poster in popularity. Even Pink Floyd tribute acts do incredibly well: Easy Star All Stars’ dub reggae revision of The Dark Side of the Moon held onto a spot in the reggae charts for five years.

This band is so popular, and has been for so long, that it’s basically impossible to imagine the rock/pop landscape without them. They’re like Isaac Asimov — many of their tropes seem hackneyed now, but that’s because everyone has been ripping them off for decades.

And yet, in spite of their impossible sales and disarming omnipresence, Pink Floyd might be the most unlikely success story in rock history — an extremely dark, thoroughly experimental group that began their career with a madman at the helm and with a (partially media-devised) affinity for scary underground drugs. The list of 60s-era pop music diktats they gleefully violated over the course of their career is too long to enumerate, but here’s a partial version:

– Do not write 25-minute songs.

– Do not devote entire albums to strange formal experiments.

– Do not neglect to release a single for much of your peak creative period.

– Do not go crazy.

– Do not sing about going crazy.

– Do not bum everyone out with harsh critiques of your society.

– Do not spit on your fans, even if they’re being rude.

And this stuff is just the beginning. Even by rock-god standards, Pink Floyd were sublimely bizarre, both as an artistic entity and as a group of people. Though it’s impossible to imagine the 2013 rock/pop landscape without them, it’s just as tough to imagine an equally daring group blowing up today.

So how did Pink Floyd get so immensely popular? Some of their success can be traced to timing and serendipity. They formed in 1965, when rock’s frontiers were wild and unexplored — there was still plenty of territory for them to pioneer. Their association with the psychedelic drug scene, accidental though it may have been, helped make them a youth-culture buzz band. Chief lyricist/bassist Roger Waters’s turn towards social and psychological ruminations in the 1970s resonated with the widespread societal soul-searching of the era. Exogenous market forces helped as well, of course. Music culture was more homogenized back then, and people still bought records.

None of this is to suggest that Pink Floyd succeeded the way they did mostly because of luck or timing. The main reason that Pink Floyd is so beloved — and this fact sometimes gets lost amidst the heaps of cultural baggage and ephemera that surround them — is because they were a fucking great band. It’s impossible for fans to even describe their sound without spewing breathless superlatives, so I won’t go down that road. (Yet.) After all, you already know what Pink Floyd sounds like. Who doesn’t?

This week, the entire Pink Floyd catalog was made available on streaming-music service Spotify, so it’s an apt opportunity for us to cull that catalog and come up with a list of the ten best Pink Floyd songs. Uh, about that: I’m not sure these are the ten best Pink Floyd songs. Hell, I’m not even sure these are my own ten favorite Pink Floyd songs.

This band released 14 albums. Some of those albums focus on oddball experimentation — Atom Heart Mother, Ummagumma, and the adapted film scores More and Obscured By Clouds. Some of them came out during transitional or waning periods in the band’s discography — Saucerful Of Secrets, The Final Cut, A Momentary Lapse Of Reason, and The Division Bell. These albums are (mostly) good, but they’re outshone by the towering brilliance of the remaining six: The Piper At The Gates of Dawn, Meddle, The Dark Side Of The Moon, Wish You Were Here, Animals, and The Wall. Big swathes of these six albums deserve to be included. To make matters more complicated, several of them are organized into unified suites that don’t break down easily. I considered including all of Dark Side and The Wall as single tunes, but that’d be a cop-out. I also elected not to unify non-consecutive suites, so you won’t see “Shine On You Crazy Diamond I-IX” or “Another Brick In The Wall (Parts 1-3).”

Ultimately, I chose the entries based on whether I’d be able to forgive myself for excluding them. (Even that didn’t really do the trick, but in the face of deadlines, ugly decisions must be made.) In the process, I left out a lot of choice cuts from the Floyd catalog. Put my picks on trial in the comments.

10. “Astronomy Domine” (from The Piper At The Gates Of Dawn, 1967)

Even 46 years after the release of “Astronomy Domine,” it remains one of the oddest tunes ever to launch the recording career of popular rock band. The vocals — usually the focal point of a rock song, especially at the time — consist of guitarist Syd Barrett and keyboardist Richard Wright chanting nonsense verse about space, which is weird enough on its own. Their surroundings get even spookier: Nick Mason’s staggering leadoff fill, Barrett’s pinched-nerve intro riff, the spiraling chromatic chorus, and producer Norman Smith’s encompassing collage of astral beeps and echo-effect clatter.

Despite being the only Pink Floyd song that lyrically deals directly with space, “Astronomy Domine” played a huge role in launching space rock, which remains in orbit today. It’s also significant because it’s the most succinct expression of Barrett’s spectacular but short-lived chemistry with Floyd. The drug-induced breakdown that eventually forced him from the band would color their work’s emotional character for the remainder of their run.

9. “Echoes” (from Meddle, 1971)

A buddy of mine used to play a fun game with this tune. When he was in college, he’d go to the local watering hole, which had a copy of Meddle in its jukebox. He’d pay for 12 songs, the first of which was always the 24-minute “Echoes.” The bartender would become agitated as soon as its opening chime cut through the air. The playlist would then return to a normal roster of boozy bar jams, until it reached its last song…which was, of course, always “Echoes.”

This isn’t Pink Floyd’s longest song; that honor goes to the ungainly but beautiful title track from Atom Heart Mother. It is, however, their first wholly successful effort at writing and recording a side-length multipart epic. Conceived in pieces and composed collaboratively by the entire band, “Echoes” cleared the path for the ambitious full-album compositions that Pink Floyd would crank out for the rest of the decade.

Fittingly, “Echoes” has echoed in other famous musical works. Check out Mason’s robotically crisp snare/closed-hat attack starting at around 7:30 of the killer Live at Pompeii version, which foreshadows Phil Selway’s drum tone on Radiohead’s OK Computer. Even more uncanny is the similarity between the song’s instrumental refrain and the overture from Andrew Lloyd Weber’s 1986 musical The Phantom Of The Opera. Waters elected not to file plagiarism litigation over the matter because, as he put it, “Life’s too long to bother with suing Andrew fucking Lloyd Weber.”

8. “Comfortably Numb” (from The Wall, 1979)

The Wall rightly has a reputation as the first of Roger Waters’s two quasi-solo albums under the Pink Floyd name. Ironically, one of its best cuts involved only a gentle touch from his creative hand. “Comfortably Numb” is mostly a David Gilmour tune; Waters contributed only lyrics and a snippet of chord work. (He also mumbles Dylan-style through the verses; the rest of the vocals are all Gilmour.)

People often confuse “Comfortably Numb” for a song about drug addiction, but Waters’s real lyrical inspiration was a 1977 incident in which he was forced to soldier through a lengthy gig in Philly while under the doctor-directed influence of tranquilizers. The real story on this tune, though, is Gilmour’s two legendary guitar solos. On the eve of the 80s, he had adopted a steely lead tone that foreshadowed the arena-metal flash of the decade to come. Of course, there’s no self-indulgent shredding here — just Gilmour’s pointillistic precision and impeccable phrasing, which are more than enough to set this drifting song ablaze.

7. “Money” (from The Dark Side Of The Moon, 1973)

“Money” is a rite of passage. Whenever a young lad or lass picks up a bass guitar and learns the ways of rock ’n’ roll rhythm, there comes a time when he or she must grapple with the challenge of odd time signatures. And when that time comes, the bass line from “Money” awaits.

Though the most iconic features of “Money” are its 7/4 verse rhythm and its opening tape loop, everything else in the song is equally great. Waters’s lyrics ridicule middle-class greed — a theme he would memorably return to several times on the albums that followed Dark Side. Wright and Gilmour dart in and out of view during the song’s first half, adding sting to the rhythm section’s sardonic funk. The lengthy lead section is outrageous—session sax man Dick Perry gets things cooking with a wheedling blues solo, which in turn sets up an explosive wet-dry-wet sequence from Gilmour. Even Mason kinda rages out beneath Gilmour’s last solo, flaunting the chops that hide behind his typically spare, metronomic timekeeping.

“Money” is a rare show of pure force on a largely abstract album; no wonder that it’s become one of Pink Floyd’s most omnipresent tunes. But it’s not quite as omnipresent as…

6. “The Happiest Days of Our Lives/Another Brick in the Wall (Part 2)” (from The Wall, 1979)

This two-song sequence is so famous and popular, so thoroughly internalized and referenced and joked around with and bitched about, that it’s almost hard to think about as actual music. It’s more of a cultural artifact now — a collectively-owned heirloom, like The Great Gatsby or Star Wars.

Ironically, even the members of Pink Floyd agree that “Happiest Days/Another Brick (Part 2)” doesn’t really sound like a Pink Floyd song. Two of its most identifiable features — Mason’s four-on-the-floor beat and the gang of children who sing the second chorus — were included at the behest of producer Bob Ezrin. Waters, who despised disco, found both ideas distasteful until he heard the fully assembled version of the song.

And it is good that he relented. Had he followed through on his original desire to write a shorter song expressing his frustration with Britain’s schooling system, the world would’ve been deprived of one of its greatest anti-authoritarian youth anthems. Even after decades of endless critical dissection and commercial overexposure, “Happiest Days/Another Brick (Part 2)” remains a song of incredible resonance. We still don’t need no thought control.

5. “Pigs (Three Different Ones)” (from Animals, 1977)

By the mid-70s, punk rock had begun to take hold in the United Kingdom. Psychedelic drugs were out; huffing glue and punching cops were in. Punk musicians and fans routinely slammed Floyd as exemplars of contemporary rock’s dowdy politics and sonic flabbiness.

These criticisms purportedly influenced Floyd’s work on Animals. You wouldn’t know it by the music itself, which sounds stark but sprawls hard — roughly 39 of its 42 minutes are spread over just three songs. It also gives more space to Gilmour’s ever-glorious soloing, which is at its weirdest on “Pigs” — he uses a talk box to imitate the titular animal’s squeal, and even rips some fretless bass leads while Waters holds down the rhythm guitar.

The lyrics on Animals are a different story. Each of those three monster tunes compares a British social caste to an animal, and the comparisons are not flattering. “Pigs” snipes at upper-crusters who cynically exploit the insecurities of others: “Bus-stop rat bag, charade you are / You fucked-up old hag, charade you are / You radiate cold shafts of broken glass / You’re nearly worth a laugh,” Waters sneers during the second verse. His notorious spitting incident took place during a performance of the song.

Oink, oink.

4. “Shine On You Crazy Diamond (Parts I-V)” (from Wish You Were Here, 1975)

The emotional aftershock of Syd Barrett’s crack-up reverberates through much of Pink Floyd’s catalog, but only “Shine On You Crazy Diamond” addresses him directly. The famous episode in which Barrett — fat, bald, disoriented, and unrecognizable to his former friends — stopped by Abbey Road Studios unannounced in the midst of the song’s mixing process is one of the saddest and most poignant anecdotes in all of rock history. Waters, who considered Barrett an avatar for the ravaging effects of 20^th-century society on the human soul, reputedly broke down in tears.

Floyd’s great sorrow over Barrett’s fate seeps from every note of their group-composed tribute to him. Waters delivers some of his most direct and heartfelt lyrics over Mason’s 6/8 sway: “Now there’s a look in your eyes / Like black holes in the sky…Come on you raver, you seer of visions / Come on you painter, you piper, you prisoner, and shine!” Wright, rarely in the spotlight, opens the song with a beautiful synth collage and supports its dramatic climax with weeping chordal organs. And the Gilmour lead that starts around 6:10? Pretty sure that’s the sound of man’s soul draining away.

3. “Brain Damage/Eclipse” (from The Dark Side Of The Moon, 1973)

These two songs are often collectively mistaken for the title track from Dark Side (there isn’t one) — “Brain Damage” uses the title as its chorus and runs seamlessly into the finale “Eclipse.”  Together, they provide the emotional zenith to one of the most seamlessly constructed albums of all time, and what a zenith it is.

It’s basically impossible to address the emotional impact of “Brain Damage/Eclipse” without discussing about the album as a whole, so instead I’ll say this: engineer Alan Parsons (yes, that one) achieved one of the great production feats of the analog era with these two tunes. The balance between spare, nervous verse and lush, organ-and-choir-driven chorus on “Brain Damage” perfectly matches the lyrics, which see Waters agonize over his psychological similarity to his crazy ex-bandmate — “And if your head explodes with dark forebodings too / I’ll see you on the dark side of the moon.” And the way that the stately, all-encompassing swing of “Eclipse” collapses, with signature Pink Floyd circularity, into the heartbeat that opens the album…yeah, you can start to understand why this peculiar little record has sold well.

2. “Dogs” (from Animals, 1977)

This song holds a special place in my heart. The first time I heard it was the (17-minute-long) moment at which I realized that Pink Floyd was no dinosaur hippie group, but a musical and emotional powerhouse that will probably never stop being relevant as long as Western civilization remains a scary, tragic place.

Like the other big tracks on Animals, “Dogs” compares humanity to its eponymous beast. It boasts the most incisive and affecting lyrics of the three, though: a brutal examination of a conniving businessman’s flaws and weaknesses. The final verse summarizes its subject’s lifetime of abjection with such devastating precision that it’s tough to listen to. Only “Shine On You Crazy Diamond” matches it for sheer intensity.

“Dogs” also marks the career high-water mark for David Gilmour’s lead playing. Since Gilmour occupies a high seat in the rock-soloist canon, “Dogs” has a considerable claim to the title of Best Guitar Song Ever. (Got a better pick? Let’s hear it.) His playing on this song channels so much heart through such economical phrasing that…well, here come the superlatives. Just listen.

1. “Wish You Were Here” (from Wish You Were Here, 1975)

Let’s be straight: every song on this list could’ve landed in the top slot. I chose “Wish You Were Here” because it’s the strongest distillation of the traits that made this band great. For all of Pink Floyd’s relentless progressivism — the superhuge songs, the rock operas, the musique concrète influence, the zany stagecraft — they would have never have achieved so much if they weren’t able to reign the weirdness in and write pristine songs. “They write great songs” is maybe the worst rock-writer cliché, but for Pink Floyd, it’s inescapably true. And this one wasn’t even a single!

“Wish You Were Here” finds all of Floyd’s finest attributes present and in perfect balance: sophisticated studio trickery, gorgeous instrumental textures, a timeless chord progression, restrained-but-powerful leads from Gilmour and Wright, a Syd Barrett nod (the “cold steel rail” line refers to a Barrett lyric from The Madcap Laughs) and a refrain that will lodge in your braincase the first time you hear it and stay there for the rest of your life. It manages this crazy achievement in just five minute and thirty-four seconds. And it organizes the whole affair around the emotion that defines Pink Floyd’s best work: an aching, cosmic loneliness that every living person has felt at one time or another.

And THAT is why this weird-ass band has sold 250 million records.

Listen to this playlist on Spotify here.