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Medal commemorating first free balloon stratospheric flight of Professor Auguste Piccard and Dr. Paul Kipfer
1931
1931
1927
2000-100 BCE
1930
1927
circa 1930
1930-1931
1932
1955; 1830
before 1928
1932
1930
1926
1926
1927
1934
circa 1927
circa 1930
circa 1930
1926
1928
1928
1927-1929
1924
1932
1931
1931
1927
Before 1932
1928
1926
1927
1928
1931
1926
1930
circa 1927
1929
1903 (original); 1982 (model)
4000-2001 BCE
1990-96
Before 1932
1930
1931
1930
1839 (original); circa 1988 (replica)
1934
circa 1929
1926
1930 (replica); 1834 (original)