On Sept. 4, 2001, System of a Down unleashed their sophomore album Toxicity. The disc, which debuted at No. 1 on the Billboard 200 album chart, took the hard-rock and metal worlds by storm with a tour de force of explosive songs, including the singles "Chop Suey!," "Toxicity" and "Aerials."

The epic album combined masterful musicianship with hard-hitting political lyrics that not only challenged societal and governmental issues, but also challenged the minds of music fans. To this day, it remains one of the best rock albums of the 21st century. In celebration of the landmark disc, Loudwire presents the following list of 10 things you may not have known about System of a Down's Toxicity.

1. The word "prison" appears 33 times in the lyrics to "Prison Song."

"Prison Song," the opening track on Toxicity, is a tune that rails against the number of people who are incarcerated in prisons across America. It admonishes the government for locking up minor drug offenders. Perhaps, System really wanted to get their point across by including the word "prison" 33 times in the lyrics, and that doesn't even include two uses of the plural "prisons."

2. It went platinum in only six weeks.

While SOAD's self-tiled debut album took three years to sell 1 million copies, Toxicity hit that total in just six weeks. In an interview with his old high-school newspaper, guitarist Daron Malakian said of the Toxicity sales, "If people say System is a sell out because we've sold millions of albums, they're wrong. I can't control how many CDs we sell or how popular we become."

3. The song "ATWA" has a link to Charles Manson.

One of the catchiest songs on Toxicity is "ATWA," a tune that combines beautifully melodic verses with an intensely chaotic chorus. The acronym stands for "Air, Trees, Water, Animals" or "All the Way Alive," and was used by Charles Manson and his associates as a term to promote the unity of life on Earth through nature.

4. SOAD recorded 33 songs during the Toxicity sessions.

A total of 40 songs were written for Toxicity, with 33 being fully recorded. The final track list included 14 songs, with many of the unused tracks leaking onto the internet under the unofficial name Toxicity II. Those additional cuts would later make up the majority of System of a Down's follow-up disc, the appropriately titled Steal This Album!

5. All three singles cracked the Top 10 of the Modern Rock Tracks chart.

The three official singles from Toxicity all climbed into the Top 10 of Billboard's Modern Rock Chart, with "Chop Suey!" reaching No. 7, "Toxicity" peaking at No. 3 and "Aerials" taking the top spot. In addition, "Aerials" also topped the Mainstream Rock Chart, making it SOAD's only song to top that tally to date.

6. Serj Tankian wrote or co-wrote the lyrics to every song on it.

Frontman Serj Tankian wrote lyrics to every song on Toxicity, with Malakian co-writing the words to six of the tunes, including "Chop Suey!" and "Aerials." Malakian, however, wrote most of the music on the album. On their subsequent albums Mezmerize and Hypnotize, Malakian contributed most of the lyric writing.

7. It topped the Billboard 200 chart the week of 9/11.

While Toxicity came out Sept. 4, its first-week sales of 220,000 units led the disc to top the Billboard 200 chart the same week as the tragic events of 9/11. The timing added more controversy to the band's rallying cry against various government policies on songs throughout Toxicity.

8. "Bounce" was featured in an animated Pixar movie.

The poodle in The Secret Life of Pets is apparently a metalhead, as his introductory scene shows him head banging to System's "Bounce" once his owner leaves. It's ironic that such a song would be included in the soundtrack of a children's movie, considering its lyrics — "Everyone gets to play / Runaway, expose / It was so exotic / But just one pogo stick."

9. The working title of "Chop Suey!" was "Suicide."

SOAD originally had "Suicide" as the title of "Chop Suey!," the first single from Toxicity. In fact, the words "We're rolling suicide" can be heard in the song's opening seconds on select pressings of the album. Despite the name change, the song was still taken off of radio by many stations because of sensitivity surrounding the 9/11 attacks at the time.

10. SOAD turned down the chance to play "Aerials" at the Grammy Awards.

While "Chop Suey!" was nominated for Best Metal Performance for the 2002 Grammy Awards, "Aerials" earned a nomination for Best Hard Rock Performance the following year. Malakian says the band turned down the chance to perform "Aerials" at the 2003 Grammys, insisting at the time, "That's something N*SYNC and Britney Spears do, not System of a Down."