313 - Roman emperor Licinius unifies the entire Eastern Roman Empire under his rule.
711 - Islamic conquest of Hispania: Moorish troops led by Tariq ibn-Ziyad land at Gibraltar to begin their invasion of the Iberian Peninsula (Al-Andalus).
1006 - Supernova SN 1006, the brightest supernova in recorded history, appears in the constellation Lupus.
1483 - Orbital calculations suggest that on this day Pluto moved inside Neptune's orbit until July 23, 1503.
1492 - Spain gives Christopher Columbus his commission of exploration.
1671 - Petar Zrinski, the Croatian Ban from the Zrinski family, is executed.
1794 - The Battle of Boulou is fought, in which French forces defeated the Spanish under General Union.
1789 - On the balcony of Federal Hall on Wall Street in New York City, George Washington takes the oath of office to become the first elected President of the United States.
1803 - Louisiana Purchase: The United States purchases the Louisiana Territory from France for $15 million, more than doubling – overnight – the size of the young nation.
1812 - The Territory of Orleans becomes the 18th U.S. state under the name Louisiana.
1838 - Nicaragua declares independence from the Central American Federation
1856 - Battle of Rivas, Nicaragua, against North American mercenaries.
1863 - Mexican forces attacked the French Foreign Legion in Hacienda Camarón, Mexico.
1871 - Camp Grant Massacre takes place in Arizona Territory.
1894 - Coxey's Army reaches Washington, D.C. to protest the unemployment caused by the Panic of 1893.
1900 - Hawaii becomes a territory of the United States, with Sanford B. Dole as governor.
1900 - Casey Jones dies in a train wreck in Vaughn, Mississippi, while trying to make up time on the Cannonball Express.
1904 - The Louisiana Purchase Exposition World's Fair opens in St. Louis, Missouri.
1920 - Peru becomes a signatory to the Buenos Aires copyright treaty.
1925 - Automaker Dodge Brothers, Inc is sold to Dillon, Read & Company for USD $146 million plus $50 million for charity.
1927 - The Federal Industrial Institute for Women, opens in Alderson, West Virginia, as the first women's federal prison in the United States.
1938 - The animated cartoon short Porky's Hare Hunt debuts in movie theaters, introducing Happy Rabbit.
1939 - The 1939 New York World's Fair opens.
1939 - RCA owned NBC begins regularly scheduled television service from its New York station with the opening ceremonies of the 1939 New York World's Fair broadcast.
1939 - Franklin D. Roosevelt becomes the first President of the United States to appear on television during the World Fair's opening ceremonies broadcast.
1943 - World War II: Operation Mincemeat – The submarine HMS Seraph surfaces in the Mediterranean Sea off the coast of Spain to deposit a dead man planted with false invasion plans and dressed as a British military intelligence officer.
1945 - Adolf Hitler and Eva Braun commit suicide after being married for one day.
1947 - In Nevada, the Boulder Dam is officially renamed Hoover Dam again.
1948 - In Bogotá, Colombia, the Organization of American States is established.
1966 - The Church of Satan is founded.
1973 - Watergate Scandal: President Richard Nixon announces that top White House aids H.R. Haldeman, John Ehrlichman, and others have resigned.
1975 - Fall of Saigon: Communist forces gains control of Saigon. The Vietnam War formally ends with the unconditional surrender of South Vietnamese president Duong Van Minh.
1980 - Accession of Queen Beatrix of the Netherlands.
1988 - French-Canadian singer Céline Dion wins the Eurovision Song Contest in Dublin, Ireland in front of 600 million TV-viewers, representing Switzerland with the song "Ne partez pas sans moi"
1991 - A tropical cyclone hits Bangladesh killing an estimated 138,000 people.
1993 - The World Wide Web was born at CERN.
1993 - During a tennis match between #1 female tennis player Monica Seleš and Magdalena Maleeva, Günter Parche plunged a steak knife between Seleš's shoulderblades. Seleš did not return to competitive tennis for over two years.
1993 - Virgin Radio (then Virgin 1215) launches in the UK at 12:15pm.
1995 - U.S. President Bill Clinton became the first U.S. President to visit Northern Ireland.
1999 - Cambodia joins the Association of Southeast Asian Nations (ASEAN) bringing the total members to 10.
2001 - The Mitchell Report on the Arab-Israeli conflict is published.
2002 - A referendum in Pakistan overwhelmingly approves the Presidency of Pervez Musharraf for another five years.
2006 - Trapped miners Brant Webb and Todd Russell at Beaconsfield, Tasmania are found alive after being unaccounted for for five days.
2007 - Last ever day where it is legal to smoke in a public building in Northern Ireland



As you may find, there are some pretty importent events that happened on this day. There are also some strange and maybe even some funny ones in here.

I figured I would start doing this since H has been doing it for a while. You need different people once in a while don't you think? 

April 30, 1945: New Generation U-Boat Too Little, Too Late

In the waning days of World War II, U-2511, under Korvettenkapitan Adalbert Schnee, puts to sea from Bergen, Norway. It marks the first and only combat patrol by a Type XXI Elektroboot, the German U-boat that profoundly influenced modern submarine design.

Luckily for the Allies, production problems and limited shipyard capacity delayed the appearance of the Type XXI until Germany was literally in her death throes. Naval experts generally agree that had the boat been accorded a higher priority in the armaments pecking order and become operational a few years earlier, the Battle of the Atlantic might have turned out very differently.

While on patrol, Schnee had the opportunity to demonstrate the new boat’s ability to elude enemy detection technology. On May 4, U-2511 evaded a destroyer screen and closed to within 500 meters of the British cruiser HMS Norfolk without being picked up by sonar. Schnee went through the preparations for firing his torpedoes, lined up the target ... and then withdrew without attacking. Schnee had received the general cease-fire order a few hours earlier, a fact he mentioned to the incredulous (and presumably relieved) Norfolk's officers a few days later when he met them in Bergen after Germany’s surrender.

If Schnee knew he was commanding a special boat, the Allies realized it soon enough, too, when a number of these boats came into their possession at war's end. The Type XXI would be used as a prototype for the design of the Cold War generation of both U.S. and Soviet subs.

Displacing 1,620 tons and armed with six forward torpedo tubes, the boat's revolutionary technology centered mostly on her ability to remain submerged for up to 60 hours at a time. There were also quantum leaps in sonar and radar technology, an area where Germany had lagged throughout the war. Outwardly, the Type XXI's influence on modern designs can be seen in her streamlined hull, which sets her apart from any other World War II-era sub.

Not that any of that did U-2511 any good. She was surrendered to the British at the end of the war and scuttled off of Northern Ireland on Jan. 7, 1946, as part of Operation Deadlight.

Link

1982 - Black Buck one (when the first vulcan bombed the Falklands).