May 20, United States detonates first hydrogen bomb

Today is Tuesday, May 20, the 140th day of 2025. There are 225 days left in the year.

Today in history:

On May 20, 1956, the United States exploded the first airborne hydrogen bomb over Bikini Atoll in the Pacific.

Also on this date:

In 1862, President Abraham Lincoln signed the Homestead Act, which was intended to encourage settlements west of the Mississippi River by making federal land available for private ownership and farming. About 10% of the land area of the United States (270 million acres, or 1.1 million square km) would be privatized by 1934.

In 1927, Charles Lindbergh took off from Roosevelt Field on Long Island, New York, aboard the Spirit of St. Louis on his historic solo flight to France.

In 1932, Amelia Earhart departed from Newfoundland in an attempt to become the first woman to fly solo across the Atlantic. (Because of weather and equipment problems, Earhart landed the following day in Northern Ireland instead of her intended destination, France.)

In 1948, Chiang Kai-shek was elected as the first president of the Republic of China (Taiwan).

In 1961, a white mob attacked a busload of Freedom Riders in Montgomery, Alabama, prompting the federal government to send in U.S. marshals to restore order.

In 1969, U.S. and South Vietnamese forces captured Ap Bia Mountain, referred to as “Hamburger Hill” by the Americans, following one of the bloodiest battles of the Vietnam War.

In 1985, Radio Marti, operated by the U.S. government, began broadcasting. Cuba responded by attempting to jam its signal.

In 2015, four of the world’s biggest banks — JPMorgan Chase, Citigroup’s banking unit Citicorp, Barclays and the Royal Bank of Scotland — agreed to pay more than $5 billion in penalties and plead guilty to rigging the currency markets.