1933/36, United States, “Century of Progress” issue
50 cent. green, Air Post (Scott C18) on FDC to Woodbury, N. J.; “First Flight Hindemburg”, 10 cent. dark blue (2), 20 cent. yellow-green, 6 cent. dull-orange (Scott C9, C10, C19) on cover with special violet handstamp. Backstamped “Frankfurt (main) 14.5.34-8-9-b” circular date stamp and “Berlin C - 14.5.36” (Siegel 409C).