CUBA (1936) Yumuri valley*. Imperforate proof block of 4 with control punches. Zona Franca del Puerto de Matanzas issue. Scott No 329, Yvert No 226.
AVAILABLE AT $40
AUSTRIA (1984) Blockheide-Eibenstein Nature Park*. Waterfall*. Black proof. Primeval landscape with "shaking rocks". Scott No 1283, Yvert No 1613.
AVAILABLE AT $20