The USA's most iconic rock band south of the Mason-Dixon Line was a relentlessly improvising juggernaut that transcended tragedies, breakups, and frequent personnel changes over four and a half decades. The dazzling slide guitarist Duane Allman and his gruff-voiced keyboardist brother Gregg formed their modal-jamming sextet in Jacksonville, Florida, in 1969, joined by co-lead guitarist Dickey Betts, bassist Berry Oakley, and a pair of powerhouse drummers in Butch Trucks and Jai Johanny Johansen, aka Jaimoe. Their earliest studio albums added future blues standards like "Whipping Post" and extended improv vehicles like "In Memory of Elizabeth Reed" to the jam-band canon, and they became bona fide stars with the 1971 release of their sprawling live album, At Fillmore East. By the end of the next year, however, both Duane and Oakley had died in motorcycle crashes. In their absence, Betts took a more prominent role on 1972’s Eat a Peach and 1973’s Brothers and Sisters, showcasing his knack for juxtaposing the bucolic (his instrumental "Jessica") with the badass (the Top-10 single "Ramblin' Man"). The broken brotherhood soldiered on before calling it quits in 1976 and, after a three-year reunion, again in 1982. What followed, though, was one of the great third acts in American entertainment. The 1989 additions of Duane Allman-channeling guitarist Warren Haynes and bassist Allen Woody, coupled with slide specialist Derek Trucks (Butch's nephew) and bassist Oteil Burbridge in the late '90s, re-energized the group: In its final incarnation, The Allman Brothers Band delivered a satisfying studio swan song with 2004’s One Way Out and performed hundreds of shows, culminating with their 238th sold-out appearance at New York's Beacon Theatre in 2014. Gregg Allman died in 2017, but the surviving members met at a packed Madison Gardens in early 2020 for one last epic jam.