Medal commemorating first free balloon stratospheric flight of Professor Auguste Piccard and Dr. Paul Kipfer
1931
1931
circa 1920
1918-1922
1926
1921
1926
1930
1927
circa 1930
1918
1931
circa 1920
1920
1920-1929
1931
1932
1955; 1830
1919
1921-1930
1920-1925
1918-1920
1932
1918
1933
1921
1918
1925-1928
1918
1920-1925
1927-1929
circa 1927
circa 1930
circa 1930
1925
1921-1926
1934
1924-1927
1922-1923
1922-1923
1922-1923
1922-1923
1920-1929
1927
1932
1920-1928
1920-1928
1923
before 1928
2000-100 BCE
1930-1931