The Beatles weren't just pop's greatest group; they were also pioneers who experimented with novel ways to release and promote music. The film clips they released in the '60s are some of the earliest examples of pop music videos. Whether it's John mugging for the camera (“We Can Work It Out”), Paul giggling at the mic (“Lady Madonna”) or the whole group larking about with an exploded piano (“Strawberry Fields Forever”), watching the palpable chemistry between all four is an infectious joy.