April 1: Battle of Okinawa: The Tenth United States Army lands on Okinawa.
April 4: American troops liberate their first Nazi concentration camp, Ohrdruf extermination camp in Germany. - The Red Army enters Bratislava and pushes to the outskirts of Vienna, taking it on April 13 after several days of intense fighting.
April 6: Sarajevo is liberated from Nazi Germany and the Independent State of Croatia (a Nazi German puppet state) by Yugoslav Partisans.
April 7: The only flight of the German ramming unit known as the Sonderkommando Elbe takes place, resulting in the loss of some 24 B-17s and B-24s of the United States Eighth Air Force. - The Japanese battleship Yamato is sunk 200 miles (320 km) north of Okinawa while en route on a suicide mission. - Kantaro- Suzuki becomes Prime Minister of Japan.
April 9: The Battle of Königsberg, in East Prussia, ends. - Abwehr conspirators Wilhelm Canaris, Hans Oster and Hans Dohanyi are hanged at Flossenberg concentration camp, along with pastor Dietrich Bonhoeffer.
April 10: The Allied Forces liberate the Nazi concentration camp, Buchenwald. - Visoko is liberated by the 7th, 9th and 17th Krajina Brigades from the Tenth Division of Yugoslav Partisan forces.
April 12: United States President Franklin D. Roosevelt dies suddenly at Warm Springs, Georgia; Vice President Harry S. Truman becomes the 33rd President.
April 14: The Canadian First Army assumes military control of the Netherlands where German forces are trapped in the Atlantic wall fortifications along the coastline.
April 15: The Bergen-Belsen concentration camp is liberated by British and Canadian forces. - The Canadian First Army reaches the coast in northern Holland and captures Arnhem.
April 16: Battle of Berlin begins. - The Canadians take Harlingen, and occupy Leeuwarden and Groningen in the Netherlands. - The Goya is sunk by Soviet submarine L-3.
April 17: Brazilian forces liberate the town of Montese, Italy, from German forces. - Inundation of the Wieringermeer in the Netherlands by occupying German forces.
April 18: American war correspondent Ernie Pyle is killed by Japanese machine gun fire on the island of Ie Shima off Okinawa.
April 19: Rodgers and Hammerstein's Carousel, a musical play based on Ferenc Molnár's Liliom, opens on Broadway and becomes their second long-running stage classic.
April 22: Heinrich Himmler, through Count Bernadotte, puts forth an offer of German surrender to the Western Allies, but not the Soviet Union. - Adolf Hitler concedes defeat in his underground Berlin bunker after learning Felix Steiner could not mobilize enough men to launch a counterattack on the Soviets who had just broken through Germany.
April 24: Retreating German troops destroy all the bridges over the Adige in Verona, including the historic Ponte di Castelvecchio and Ponte Pietra.
April 25: Founding negotiations for the United Nations begin in San Francisco. - Elbe Day: United States and Soviet troops link up at the Elbe River, cutting Germany in two.
April 25-26: Last major strategic bombing raid by RAF Bomber Command, the destruction of the oil refinery at Tonsberg in southern Norway by 107 Avro Lancasters.
April 26: Battle of Bautzen: The last "successful" German panzer-offensive in Bautzen ends with the city recaptured. - The British 3rd Infantry Division under General Whistler captures Bremen. - Nazi surrenders mean the British and Canadians now control the German border with Switzerland from Basle to Lake Constance.
April 27: U.S. Ordnance troops find the coffins of Frederick William I of Prussia, Frederick the Great, Paul von Hindenburg, and his wife. - The Western Allies flatly reject any offer of surrender by Germany other than unconditional on all fronts.
April 28: Benito Mussolini and his mistress, Clara Petacci, are executed by Italian partisans as they attempt to flee the country. Their bodies are then hung by their heels in the public square of Milan. - The Canadian First Army captures Emden and Wilhelmshaven.
April 29: At the royal palace in Caserta, Lieutenant-Colonel Viktor von Schweinitz (representing General Heinrich von Vietinghoff) and SS-Obersturmbannfuehrer Eugen Wenner (representing Waffen-SS General Karl Wolf) signs an unconditional instrument of surrender for all Axis powers forces in Italy, taking effect on May 2. Italian General Rodolfo Graziani orders the Esercito Nazionale Repubblicano forces under his command to lay down their arms. - Brazilian forces liberate the commune of Fornovo di Taro, Italy, from German forces. - Operation Manna: British Avro Lancaster bombers drop food into the Netherlands to prevent the starvation of the civilian population. - Adolf Hitler marries his longtime mistress Eva Braun in a closed civil ceremony in the Berlin Führerbunker.
April 30: Death of Adolf Hitler: Adolf Hitler and his wife of one day, Eva Braun, commit suicide as the Red Army approaches the Führerbunker in Berlin. Karl Dönitz succeeds Hitler as President of Germany; Joseph Goebbels succeeds Hitler as Chancellor of Germany. (source: Wikipedia)