How did Busby Berkeley's choreography help make 42nd Street memorable?

In the 1933 musical film 42nd Street, directed by Lloyd Bacon, the choreography of Busby Berkeley was instrumental in transforming the genre and ensuring the film's enduring success.1

Berkeley’s contribution was defined by his ambitious production numbers, which utilized innovative cinematography to capture dancers from unconventional perspectives. Most notably, he employed overhead camera angles that created elaborate, kaleidoscopic patterns with the performers, a technique that was revolutionary for the era. By integrating these visually spectacular sequences into the narrative, Berkeley helped elevate the film beyond its standard plot elements, establishing 42nd Street as a classic that successfully merged dramatic storytelling with grand-scale musical spectacle.21