Slipknot (band)

Context: Anticipation for Slipknot's second album was intense. In early 2001, the band began recording the second album at Sound City and Sound Image studios in Los Angeles. Around this time, conflicts arose between band members due to extensive touring and recording schedules. Recording of their second album ended in February 2001 and the band embarked on their Iowa World Tour. Entitled Iowa, Slipknot's second album - released on August 28, 2001 - peaked at number three on the Billboard charts and at number one in the UK. The album produced three singles; "The Heretic Anthem" (promotional single), "Left Behind", and "My Plague", which appeared on the soundtrack for the film Resident Evil. In 2002, Slipknot appeared in Rollerball (2002), performing "I Am Hated". The release and intense promotion of the album resulted in sold-out shows in large arenas in several countries.  In mid-2002, Slipknot went on hiatus because of internal conflicts, and band members focused on side projects. Vocalist Taylor and guitarist Root revived their band Stone Sour, drummer Jordison created Murderdolls with vocalist Wednesday 13, percussionist Crahan founded To My Surprise and DJ Wilson went solo as DJ Starscream. For a while, the future of Slipknot was uncertain and there was much speculation about whether there would be a third album, or if the split would become permanent. "I don't have a problem with anyone in Slipknot," Jordison protested. "I've seen comments from Corey saying there are things to be resolved, but I have no fucking idea what he's talking about."  Nonetheless, on November 22, 2002, Slipknot released their second DVD, Disasterpieces.  Preparation for Slipknot's fourth album began towards the end of 2007; work began at Sound Farm Studio in Jamaica, Iowa, with producer Dave Fortman in February 2008. The album was finished in June, and the band the All Hope Is Gone World Tour on July 9, 2008. Slipknot's fourth album, All Hope Is Gone, was released on August 20, 2008, debuting at number one on the Billboard albums chart. The album produced five singles; "All Hope Is Gone", "Psychosocial", "Dead Memories", "Sulfur" and "Snuff". 2009 marked the 10th anniversary of Slipknot's debut album; to commemorate the event, the band released a special edition version of Slipknot on September 9, 2009. The band toured in support of the album throughout 2008 and continued until October 31, 2009, resulting in Slipknot's third hiatus.  During the hiatus, several band members focused on respective side projects; Taylor founded Junk Beer Kidnap Band and returned to Stone Sour with guitarist Root; Crahan continued working with his band Dirty Little Rabbits; and drummer Jordison returned with his band Murderdolls and became the new permanent drummer of Rob Zombie. Percussionist Fehn is now a full-time bassist with metalcore band Will Haven and Sid Wilson founded the eponymous band Sid.  In 2010, Gray was planning to tour with the supergroup, Hail!, but on May 24, 2010, he was found dead in an Urbandale, Iowa hotel room. Circumstances surrounding his death at the time were not immediately known; an autopsy suspected his death was not intentional but did not reveal the cause. The day after his death, the remaining eight members of the band held a live, unmasked, press conference alongside Gray's widow and brother. On June 21, the cause of death was confirmed as an accidental overdose of morphine and synthetic morphine substitute fentanyl.  The band was hesitant to comment on the future of Slipknot. The members made conflicting statements in interviews; drummer Jordison told The Pulse of Radio "there is another Slipknot record already kinda in the making". Vocalist Taylor told FMQB Productions' he was "very conflicted about whether or not [he wants] to do anything with Slipknot". The band released their fourth video album (sic)nesses on September 28, 2010; it debuted at number one on the Billboard Top Music Video Charts. The DVD features Slipknot's entire live performance at the 2009 Download Festival and a 45-minute film documenting their tour in support of All Hope Is Gone, and served as a tribute to Paul Gray.  Regarding the continuation of Slipknot, Taylor told NME Gray would want them to continue and he felt they should but he was ambivalent about returning to the band. Slipknot returned to touring in 2011, performing a small number of shows in Europe. They headlined the Sonisphere Festival and Rock in Rio alongside Iron Maiden and Metallica, and performed at Belgium's Graspop Metal Meeting. Donnie Steele substituted for Gray in the concerts; he was positioned behind Jordison and obscured from the audience's view.  Slipknot also said the band would complete and release the band's fifth studio album, and that there were no plans to replace Gray. Jordison said the writing process for the album had already begun and that he had written 17 songs. Slipknot performed at the Mayhem Festival tour of 2012.  On May 29, 2012, Roadrunner Records posted a teaser video titled Antennas to Hell on its website. Later that day, on Twitter, Corey Taylor said Slipknot will release a greatest hits album on June 17, 2012. He also said the band was not yet recording new material but was putting together demos for a new album.  Slipknot's first annual music festival, called Knotfest, was held on August 17, 2012, at Mid-America Motorplex near Pacific Junction, Iowa, and on August 18, 2012, in Somerset, Wisconsin. Deftones, Lamb of God, Serj Tankian also performed at the festival. The festival shows also debuted a Slipknot museum. On 14, June 2013, Slipknot headlined the Download Festival for a second time. The band performed to roughly 90,000 people and was twice forced to stop the set--once in the middle of a song--to allow the front barricade, which had split open under crowd pressure, to be repaired. CANNOTANSWER

Question: How successful was Knotfest?
Answer: 90,000 people