Events on April 4 in history

World War II: First bombardment of oil refineries in Bucharest by Anglo-American forces kills 3000 civilians.

Failed empty result.

10 Apr

Auschwitz concentration camp
Rudolf Vrba and Alfréd Wetzler escape from Birkenau death camp.
13 Apr

Soviet Union
Diplomatic relations between New Zealand and the Soviet Union are established.
26 Jun

RAF
World War II: San Marino, a neutral state, is mistakenly bombed by the RAF based on faulty information, leading to 35 civilian deaths.
26 Aug

Charles de Gaulle
World War II: Charles de Gaulle enters Paris.
31 Dec

Nazi Germany
World War II: Hungary declares war on Nazi Germany.