One significant figure in the jazz movement is Louis Armstrong. His innovative trumpet playing and distinctive voice helped popularize jazz worldwide. Armstrong's contributions to music history include the development of scat singing and transforming jazz into a soloist's art form. His interpretations of songs like "What a Wonderful World" and "Hello, Dolly!" showcased his improvisational skills and emotional expression. Armstrong's ability to bridge racial divides through his music made him a cultural icon, influencing generations of musicians and shaping the American music landscape.