Complex sentence: San Juan, Puerto Rico was commemorated with an 8-cent stamp on its 450th anniversary issued September 12,1971, featuring a sentry box from Castillo San Felipe del Morro.
Split into simpler sentences: San Juan, Puerto Rico was commemorated with an 8-cent stamp on its 450th anniversary issued September 12,1971. The vignette pictures a sentry box from Castillo San Felipe del Morro.