8 on the Uk singles charts earning the band immense popularity in Europe. Drummer Frank Cook left the band in December 1967 and was replaced by Adolfo "Fito" de la Parra. Canned Heat's third album included the band's best-known song, also sung by Wilson, "Going Up the Country." The song, an incarnation of Henry Thomas' "Bull-Doze Blues" was rewritten by Wilson and caught the "back to nature" attitude of the late 1960's. The tune was a hit in numerous countries around the world, peaking at number 11 in the US. The "rural hippie anthem" became the unofficial theme song for the Woodstock Festival where Canned Heat performed at sunset on August 16, 1969. Although Canned Heat's live performance was cut from the original theatrical release of the Woodstock film, they were featured in the 25th anniversary "Director's Cut." The studio version of "Going Up the Country" was featured in the Woodstock film; and in recent years has been heard in television commercials for Geico Insurance, Subaru, and Pepsi. Around this time, Wilson started to become disillusioned with Canned Heat and considered quitting on several occasions. Upset over Vestine's departure and becoming more adversed to touring, Wilson expressed the possibility of still recording but not touring with the band. Wilson arranged to join Vestine's new band Sunn, and Frank Cook's group Pacific Gas and Electric, however both options fell through. Eventually Wilson did end up quitting Canned Heat for about 2 weeks in late 1969, and again shortly before his death in 1970. But each time, he felt guilty and decided to go on tour again. His increasing isolation became obvious, as footage of the band at this time showed Wilson standing apart from his bandmates, and often hiding behind rows of amps. Canned Heat's fifth album Future Blues was released in August 1970 and featured the Wilbert Harrison cover of "Let's Work Together." It became their biggest hit in the UK, reaching number 2 on the Singles Chart for 15 weeks. The cover features the band dressed as astronauts on the Moon mocking the flag raising at Iwo Jima. The upside-down American flag was Wilson's idea in response to the country's social distress at the time, and his concern over the Moon landing a year before. However, retailers like Sears and K-Mart found the cover offensive and refused to stock the album. In May 1970, Canned Heat teamed up with