Togo issued a set of four stamps on May 1,
1960 to mark a Summit Conference between France Great Britain, the
United States and the USSR which was to begin on May 16. On May 1 a US
reconnaissance plane piloted by Francis Gary Powers intruded into
Soviet airspace and was shot down. As a result President Khrushchev of
the USSR left Paris and the Summit was not held. Powers was imprisoned
by almost two years before he was exchanged for Rudolf Abel in 1962.
The title in the upper, left corner of the stamps should not
be "Congrès des Sommet," but rather "Congrès au Sommet," or
"Confèrence au Sommet" according to Jean-Pierre Mangin.