AUSTRIA (2013) Postojna cave*. Black print of SS.
AVAILABLE AT $25
BELGIUM (1991) Neptune's grotto. Ministerial proof. Scott No 1403, Yvert No 2410. Tourist attractions.
AVAILABLE AT $50
CUBA (1936) Bellamar Caves*. Imperforate proof block of 4 with control punches. Zona Franca del Puerto de Matanzas issue. Scott No 328, Yvert No 225.
AVAILABLE AT $40
AUSTRIA (1994) Peggau Cave, Styria*. Black proof. Scott No 1496, Yvert No 1952.
AVAILABLE AT $15