On this date

In 1900, U.S. Secretary of State John Hay announced the “Open Door Policy” to facilitate trade with China. In 1921, religious services were broadcast on radio for the first time as KDKA in Pittsburgh aired the regular Sunday service of the city’s Calvary Episcopal Church. In 1935, Bruno Hauptmann went on trial in Flemington, N.J., on charges of kidnapping and murdering the 20-month-old son of Charles and Anne Lindbergh. (Hauptmann was found guilty and executed.)

In 1967, Republican Ronald Reagan took the oath of office as the new governor of California in a ceremony that took place in Sacramento shortly after midnight.

In 1974, President Richard Nixon signed legislation requiring states to limit highway speeds to 55 mph as a way of conserving gasoline in the face of an OPEC oil embargo. (The 55 mph limit was effectively phased out in 1987; federal speed limits were abolished in 1995.)

In 1991, Sharon Pratt was sworn in as mayor of Washington, D.C., becoming the first black woman to head a major U.S. city.

In 2006, a methane gas explosion at the Sago Mine in West Virginia claimed the lives of 12 miners, but one miner, Randal McCloy Jr., was eventually rescued.

Ten years ago: Oil prices soared to $100 a barrel for the first time.

Five years ago: The United Nations gave a grim new count of the human cost of Syria’s civil war, saying the death toll had exceeded 60,000 in 21 months. One year ago: A suicide bomber driving a pickup loaded with explosives struck a bustling market in Baghdad, killing at least 36 people in an attack claimed by the Islamic State group.