When "La Casa de Papel" premiered as a two-part miniseries on Spain's Antena 3 in the spring of 2017, critics praised the thrilling caper — about a group of criminal masterminds who pull off a daring heist at the Royal Mint — for its absorbing pilot, powerful premise and boundary-pushing plot. But by the time the second half premiered that fall, enthusiasm (and viewership) had cooled enough to render the 15-episode series a virtual flop.

That would have been the end of "La Casa de Papel," known in the United States as "Money Heist," if not for Netflix, which picked up the show at the end of 2017, repackaged it into shorter episodes across two seasons, and ordered a third and fourth installment. The show's presence on the streaming platform, where the first half of its fifth and final season arrived earlier this month, elevated "Money Heist" into a global cultural phenomenon that has inspired memes, Halloween costumes and one very memorable line in a chart-topping Latin pop song.

"Money Heist" wasn't Netflix's first Spanish-language original (that would be "Club de Cuervos," a Mexican dramedy released in 2015), but it was the first to find a decidedly international audience. Its popularity prompted Netflix to invest in other series set in Spain, including the prep-school thriller "Elite," which premiered to notable buzz in 2018 and has been renewed for a fifth season. "Money Heist," set to drop its five remaining episodes this December, is rightfully celebrated as a forebear to other non-English language hits including "Lupin," a French mystery thriller, and the Mexican whodunit "Who Killed Sara?"

By all accounts, the show's post-Netflix success came as a surprise to its cast and creator Álex Pina — not least because it launched with little promotional fanfare on the platform. In a 2020 Netflix featurette called "Money Heist: The Phenomenon," cast members including Jaime Lorente and Miguel Herrán recall noticing their follower counts rapidly increasing on Instagram after the show's quiet streaming debut. That was the first of many signs the series, which won an international Emmy for best drama in 2018, had resonated with audiences around the world.

After Part 3 arrived on the platform in 2019, Netflix said that the new installment had been watched by more than 34 million households, breaking a record for a non-English title. Last year, "Money Heist" became an early entry in Netflix's Top 10 list, drawing 65 million viewers — more than the ubiquitous and controversial "Tiger King," according to the streamer.

Netflix, which is selective about the metrics it shares publicly, has not released information on how viewers take in the Spanish-language series — dubbed or via subtitles — but Álvaro Morte, who plays the enigmatic ringleader known as the Professor, recently told Variety he realized the show's vast reach after learning that some viewers had been spurred to overcome the language barrier. "I've heard that people around the world started studying Spanish because of 'Money Heist,' just because they wanted to hear our real voices," he told the magazine. "You can't help but be proud of that."

Pop culture also reflects the influence of "Money Heist," which has attracted a fan base including Stephen King, who excitedly donned a Salvador Dalí mask like the one the robbers wear on his social media ahead of the show's third installment. After professing his love for "Money Heist," Brazilian soccer star Neymar made a cameo in the third season. Bad Bunny's verses have revealed the rapper's affinity for the series: He famously shouts out Nairobi (Alba Flores) in "Yo Perreo Sola," comparing the song's fiercely independent protagonist to the fan-favorite thief. He also references the show's narrator Tokyo, played by Úrsula Corberó, on the "Como Se Siente" remix featuring Jhay Cortez.

"Money Heist's" increased profile helped lead the show's cast to international fame, and several actors from the series have talked about being increasingly overwhelmed with autograph requests. In the Netflix special, Pedro Alonso, who plays robber Berlin, recalled the crew having to stop filming in Italy because fans had swarmed the plaza serving as a production location. The show's popularity has also led to other visible roles: Last year, Corberó starred in the music video for "Un Dia (One Day)," which features Bad Bunny alongside J Balvin, Dua Lipa and producer Tainy.

As for why "Money Heist" fizzled on Spanish TV, one expert told Variety it may have something to do with the country's late-night schedule; the first episode, for example, premiered on Antena 3 following a Real Madrid game that kicked off at 8:45 p.m. "Episodes are often 100 minutes long and sometimes don't start until 11:30 p.m.," European TV scholar Christopher Meir told the magazine. "No matter how popular the show, they almost always lose momentum."

Momentum is exactly what "Money Heist" fans have going into the show's last season, despite pandemic-related delays. Pina told Variety he and the show's writers went back to the drawing board on early Season 5 episodes, writing "each as if they were the season finale, with that kind of nerve and energy."

"That strategy kept going," he added. "I think that audiences will feel that almost every episode of Part 5 feels like a finale."