Medal commemorating first free balloon stratospheric flight of Professor Auguste Piccard and Dr. Paul Kipfer
1931
1931
1930
circa 1930
1931
1931
1932
1955; 1830
1932
circa 1930
circa 1930
1934
1932
before 1928
2000-100 BCE
1930-1931
Before 1932
1928
1928
1928
1930
1924
1930 (replica); 1834 (original)
1930
1929
1903 (original); 1982 (model)
1990-96
1929
circa 1929
1930
1930-1932
1930-1932
1930-1932
1930
Before 1932
1934
1830 (original); 1967 (model)
1930
1931
1931
4000-2001 BCE
1801-1892 (prepared); 1946 (element replaced)
1931
1928
1932
circa 1930s
1930s
circa 1931
circa 1932
circa 1932
1930s