The late 1990s saw a huge surge of anime coming to the United States thanks to the success of series such as Pokémon, Sailor Moon, and Gundam. One of the most impactful series, however, was Cowboy Bebop, which celebrates its 20th anniversary this month, having debuted in Japan on April 3, 1998 before arriving in North America via Cartoon Network’s Adult Swim block in 2001.

The story focused on bounty hunter Spike Spiegel and his partner Jet Black in the future of 2071, who are later joined by the con artist Fay Valentine, hacker Edward Wong and the genetically-enhanced corgi dog Ein. Each character’s story arc gets a focus throughout the series, though the main plot follows Spike as he battles against his rival and former partner Vicious, who harbors a grudge against Spike. The two were once friends, though things went awry after Spike began an affair with Vicious’ girlfriend, Julia.

The series was known for its film noir stylings that also included elements of thrillers, capers, and straight up comedy. It is also widely remembered for its music, which was composed by Yoko Kanno and focused heavily on jazz and blues. Since Cowboy Bebop’s original broadcast, Kanno and her band, the Seatbelts, have released seven different original soundtracks from the show.

Cowboy Bebop was Shinichiro Watanabe’s directorial debut. He later worked on other critically-acclaimed series such as Samurai Champloo, Space Dandy, and Terror in Resonance. Watanabe mixed several genres within Cowboy Bebop, balancing classic detective and noir tropes with action and comedy. A film, Cowboy Bebop: The Movie released in 2001 in Japan and two years later in the U.S. Multiple video games were also released in Japan, though they never made their way west despite the series’ popularity in North America.

The series received critical acclaim in every market it was released in, and the English dub was also widely praised for the voice acting involved. It picked up multiple Anime Grand Prix awards in Japan when it launched, and has been listed as one of the single best anime series of all-time by publications in both Japan and in America. Even now, two decades after it launched, Cowboy Bebop remains one of the most popular series out there and has clearly stood the test of time.