BELGIUM (1931) Han Grotto*. Postal card (N) with corner illustration.
AVAILABLE AT $20
GERMANY (1966) Stalactites and stalagmites in cave in Lichtenstein. Postal card (N) with corner illustration.
AVAILABLE AT $15
GERMANY (1968) Ice age cave converted to 14th century church (Scharzfeld)*. Postal card (N) with corner illustration.
AVAILABLE AT $15
AUSTRALIA (1917) Narracoorte Caves, SA*. Illustrated lettercard (used). LC18-89.
AVAILABLE AT $50