Louis Armstrong and Dave Brubeck were influential figures in 20th-century jazz. Armstrong, a gifted trumpet player and singer from New Orleans, revolutionized jazz by introducing an improvisational, solo-oriented style, with his expressive voice and virtuosic playing defining classics like "What a Wonderful World" and "Hello, Dolly!". Brubeck, a pianist and composer from California, was known for his innovative use of rhythm and time signatures, as evidenced in his signature piece, "Take Five." Together, they contributed significantly to the evolution of jazz, impacting countless musicians and shaping the genre's progression.