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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
1925
1921-1926
1930
1927
1924
1925
circa 1930
1930-1931
1922
1932
1955; 1830
before 1928
1932
1925-1927
1930
1926
1921
1926
1934
1924
1927
1923
1934
1923
1934
circa 1927
circa 1930
1924-1927
circa 1930
1934
1934
1926
1933
1928
1928
1921-1931
1921
1925-1928
1927-1929
1924
1922-1923
1922-1923
1922-1923
1922-1923
1921-1930
1932
1931