You may argue that the atomic theory developed by Niels Bohr is not strictly a discovery or an invention. However ts importance cannot be denied.
Denmark issued commemorative stamps for the 50th anniversary of his theory which has stood the test of time.
Denmark - 21 November 1963 |
It was in the 1950s when I first became aware of his work when studying atomic physics as part of my degree course at St Andrews University.
For more theories, discoveries and inventions check out the links at The Fathers of Invention