April 30

311 – Under the Edict of Toleration by Emperor Galerius, the persecution of Christians under an edict of Emperor Diocletian is ended in the Eastern Roman Empire.

1492 – 13 days after acceding to his demands and granting him his titles, King Ferdinand and Queen Isabella formally present Viceroy, Governor General and Admiral of the Ocean Sea, Don Christopher Columbus, his commission of exploration.

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 President of the United States under the Constitution. In November 1781, John Hanson became the first President of the United States in Congress Assembled, under the Articles of Confederation.

1803 – The United States purchases the Louisiana Territory from France for $15 million.

1812 – The Territory of Orleans becomes the 18th U.S. state under the name Louisiana.

1885 – Governor of New York David B. Hill signs legislation creating the Niagara Reservation, New York’s first state park; Niagara Falls.

1900 – Hawaii becomes a territory of the United States.

1927 – The Federal Industrial Institute for Women opens in Alderson, West Virginia, the first women’s federal prison in the U.S.

1939 – NBC begins regular scheduled television broadcasting in New York City, televising President Roosevelt’s N.Y. World’s Fair opening day ceremonial address.

1943 – Completing Operation Mincemeat during World War II, British Royal Navy submarine HMS Seraph surfaces near Huelva, Spain to cast adrift a dead man dressed as a Royal Marine courier and carrying false invasion plans for Greece and Sardinia, as a ruse for the invasion of Sicily.

1945 – In the Führerbunker in Berlin, Adolf Hitler takes cyanide and then blows his brains out with a pistol, while Eva Braun simply takes cyanide to commit suicide.

1947 – In Nevada, Boulder Dam is renamed Hoover Dam.

1948 – In Bogotá, Colombia, the Organization of American States is established.

1956 – Former Vice President, under President Truman, and Democratic Senator Alben Barkley collapses dies during a speech at the Washington and Lee university in Lexington,Virginia.

1973 – President Nixon announces that White House Counsel John Dean has been fired and that other top aides, H. R. Haldeman and John Ehrlichman, have resigned due to the Watergate Burglary scandal.

1975 – The U.S. completes a hasty evacuation of Saigon while Communist forces gain control of the city. The Vietnam War ends with the unconditional surrender of South Vietnamese president Dương Văn Minh.

1993 – CERN announces World Wide Web protocols will be free.

2012 – The unfinished One World Trade Center overtakes the Empire State building to become the tallest building in New York.