On Dec. 14, 1979, the English punk band The Clash released their third studio album, London Calling. Immediately it was recognized both commercially and critically, garnering positive reviews from nearly every music publication at the time and was certified gold in both the United States and United Kingdom within months of release.

It’s a fact that it’s one of the most celebrated rock albums of all time, regularly making its way onto top lists of celebrated music publications, but what exactly makes this album what it is?

It’s almost a manic collection of genres, influences, but rather than sounding cluttered and lost like many other bands who have tried the kitchen sink style songwriting, London Calling has a unique sound that has endured and will continue to endure for generations to come.

This is an album that is hard to fit into a single or even multiple genre definitions. It’s been described by several critics as post punk, and while the album does follow the post punk trend of experimenting with different music styles to express the punk style, The Clash stick out among other post punk contemporaries like the Talking Heads or Joy Division because of how bright and large their compositions can sound.

For example, the album kicks off with the title track “London Calling,” which is backed by a very traditional sounding punk arrangement featuring pounding guitar and bass lines and Joe Strummer’s lead vocal cutting out angsty, politically charged vocals. After this, however, comes a punk style cover of the rockabilly blues track Brand New Cadillac.

The whole album is a mix of these different kind of styles, like the extremely reggae sounding “Guns of Brixton” and “Lover’s Rock” or the inspirational anthemic tracks like “I’m Not Down” and “Train In Vain.” The Clash keeps all these tracks mostly grounded in punk, though, resulting in a sound that’s both consistent and varied, palatable and experimental, and iconic yet very personal and individual on each track. The double album length also gives the band a significant amount of time to flesh out the ideas presented and flex their creative muscles, as pretty much every single track is an amazing and different experience.

The production on this album is also a part of its lasting appeal, as time goes on and music keeps sounding better (or worse, as lo-fi indie projects produced in a basement gain more and more traction), the techniques and performances on this album remain solid.

The compositions on this album sound great, Joe Strummer’s lead vocals are fleshed out with solid backing vocals by Mick Jones and Paul Simonon that really come full circle and provide a full and satisfying sound when accompanied by the consistently fantastic guitars, drums, and various other instruments such as the saxophone or harmonica that pop up along the way.

Whatever genre or identifier you want to apply to London Calling, it’s an album that consistently provides amazing and interesting sounds and music.