As one of the key figures of the British Invasion and the mod movement of the mid-'60s, the Who were a dynamic and undeniably powerful sonic force. They often sounded like they were exploding conventional rock and R&B structures with Townshend's furious guitar chords, Entwistle's hyperactive bass lines and Moon's vigorous, chaotic drumming. Unlike most rock bands, the Who based their rhythm on Townshend's guitar, letting Moon and Entwistle improvise wildly over his foundation, while Daltrey belted out his vocals. This was the sound the Who thrived on in concert, but on record they were a different proposition, as Townshend pushed the group toward new sonic territory. He soon became regarded as one of the finest British songwriters of his era, as songs like "The Kids Are Alright" and "My Generation" became teenage anthems, and his rock opera, Tommy, earned him respect from mainstream music critics.