The British Invasion occurred in the mid-'60s, when a wave of English rock & roll bands crossed over into the American market after the breakthrough success of the Beatles. Though not all of the bands sounded similar -- they ranged from the hard rock of the Rolling Stones and the Kinks to the sweet pop of Gerry & the Pacemakers and Herman's Hermits -- each group was heavily influenced by American rock & roll, blues, and R&B. British Invasion bands were either blues-based rockers or pop/rockers with ringing guitars and catchy hooks & melodies. Between 1964 and 1966, the British bands dominated the American charts, as well as the charts in the U.K. In that time, there was a second wave of British Invasion bands -- such as the Who and the Zombies -- which was indebted to both American rock and British Invasion pop. By the late '60s, many of the bands had become rock icons but a greater number didn't survive the transition into the post-"Sgt. Pepper" era.