On this day 25th June

Year What
841 Charles the Bald and Louis the German defeat Lothar at Fontenay.
1215 Magna Carta is sealed
1903 Marie Curie announces her discovery of Radium
1941 Finland declares war on Russia
1943 The audacious and masterful Dambusters raid strikes the Nazi industrial heartland
1948 The Soviet Union tightens its blockade of Berlin by intercepting river barges heading for the city