It’s been 20 years since Arctic Monkeys formed in their hometown of Sheffield, UK; since then, they’ve become one of the most revered and culturally significant rock bands in Europe and beyond. It’s one thing to consider how quickly their 2006 debut album, Whatever People Say I Am, That’s What I’m Not, brought the group widespread success, but another to examine what they’ve done with that level of visibility over the last 15 years.

Their debut was a scrappy, infectious introduction to a band that was not concerned with being everything to everybody, as its title suggests — but from there, Arctic Monkeys rightfully decided that each ensuing album would be done on their own terms, and they continued to hone and expand their enigmatic indie rock style throughout the next two decades. Their sophomore album Favourite Worst Nightmare found the band leaning into a frenetic chaos harder than ever before, like the irreverent bombast of “Brainstorm” and “This House Is A Circus,” while tapping into a much more mature and emotional center, like on highlights “505” and “Do Me A Favour.”

The band continued their world domination with the Josh Homme-produced Humbug, which once again dismantled any preconceived notions about what Arctic Monkeys were supposed to sound like. Their fourth album, Suck It and See, was arguably their least successful, but still proved to be a rich, thoughtful turn from the quartet. And then came 2013’s AM, which solidified the group as headliners beyond their home country and saw the band double down on their stylish, retro impulses.

AM was such a massive turning point for Arctic Monkeys that their next effort had to be, frankly, another left turn. Tranquility Base Hotel & Casino, which followed, is the wonkiest, weirdest album that the band has released to date. Turner’s surrealist ramblings and his unreliable, frequently hilarious cast of characters is, somehow, Turner at his most uninhibited and specific at the same time.