Registered cover with manuscript 'Carlos Bohn, Monte Carlos, Argentina, S.A.' return address on reverse franked with pair 1923 12c blue 'San Martin' issue (SG 520) tied by PUERTO MONTE CARLO-Mi cds dated 21 AGO 1929 with plain black & white registration label alongside. Addressed to GERMANY with BUENOS AIRES transit cds and German arrival cds's on reverse. Puerto Monte Carlo was a German & Swiss settlement established in 1920. Very scarce.