Medal commemorating first free balloon stratospheric flight of Professor Auguste Piccard and Dr. Paul Kipfer
1931
1931
circa 1920
1935
1926
1930-1940
1943
1920-1940
1921
1926
1942
1943
1925-1940
1930
1940
1927
1938
1940
1938
1938
1938
1935
1938
circa 1930
1940
1931
1942
circa 1920
1920
1935
1940
1936
1920-1929
1934
1929-1935
1936
1931
1937
1937
1935
1938
1938
1932
1955; 1830
1921-1930
1934
1930-1940
1920-1925
circa 1938
1935
1932