12 Bar Blues is a sequence of chords which repeats every twelve bars. There are hundreds of well known songs based on this chord progression, i.e., they contain basically the same chords in the same order. 12 Bar Blues is commonly used in Rock music and is the basis of Blues music. There have been many hit songs by artists such as Chuck Berry, The Beatles, Elvis Presley, Little Richard, The Beach Boys, B.B. King, Jimi Hendrix, Led Zeppelin, AC/DC, Van Halen, Joe Satriani, Gary Moore, Robert Cray, Stevie Ray Vaughan and Eric Clapton which are based on this progression. Here are some well known songs which are based on the 12 Bar Blues progression.
Listen to this typical 12 Bar Blues. The progression is in the key of C. The symbol C which appears above some of the bars is a bar repeat sign. It indicates that this bar is identical to the previous one. The last two bars of the progression are called the turnaround, an ending which leads to the next verse.