Medal commemorating first free balloon stratospheric flight of Professor Auguste Piccard and Dr. Paul Kipfer
1931
1931
1935
1930
1935
circa 1930
1931
1935
1936
1934
1929-1935
1936
1931
1937
1937
1935
1932
1955; 1830
1934
1935
1932
1933
circa 1930
circa 1930
1936
1934
1935
1932
before 1928
2000-100 BCE
1930-1931
Before 1932
1937-1937
1928
1934
1929-1935
1935
1933
1936
1928
1935
1928
1934
1930
1924
1930-1935
1936
1937
1937
1933
1930 (replica); 1834 (original)