Answer: a, b, c, d

On October 24, 1861, upon completion that day of the first transcontinental telegraph line by workers of the Western Union Telegraph Company, the first telegram from California to Washington, D.C. was sent by California Chief Justice Stephen J. Field to President Abraham Lincoln.

On October 24, 1901, Annie Edson Taylor, a 63-year-old schoolteacher, became the first person to ride over Niagara Falls in a barrel.

On October 24, 1945, the United Nations formally came into being upon ratification of the U.N. Charter by a majority of nation-states and all five permanent members of the Security Council.

On October 24, 2003, British Airways' remaining Concorde jets took their final passenger flights, ending 27 years of commercial supersonic transportation.