Nishizawa painted his first major mural “El aire es vida y la salud es la mayor riqueza” at the Centro Médico Nacional Siglo XXI, with another shortly after in 1969 at the Hospital General de Zona No.
Nishizawa produced his initial significant mural, "The air is life, and health is the greatest wealth," at the Centro Médico Nacional Siglo XXI in 1969. He also painted another mural there or elsewhere around that time.