Louis Armstrong was an American jazz trumpeter and singer whose joyful, inventive playing helped shape jazz into one of America's greatest art forms. His warm, gravelly singing voice and dazzling trumpet solos made him one of the most beloved musicians of the 20th century. He helped pioneer scat singing, famously improvising nonsense syllables in his 1926 recording of "Heebie Jeebies," and his 1964 hit "Hello, Dolly!" knocked The Beatles off the top of the charts, making him, at 62, the oldest artist ever to have a number-one single. He toured the world for decades, spreading jazz and his famous wide smile to audiences everywhere.