1895: Italian inventor Guglielmo Marconi sends telegraphic signals by radio a distance of about a mile.
1906: Reginald Fessenden, a Canadian-born physicist, speaks to ships at sea by radio from Brant Rock, Mass.
Nov. 2, 1920: KDKA broadcasts the results of that day's presidential election - Warren Harding defeats James Cox. It is heard on about 500 to 1,000 radios.
Oct. 5, 1921: The first World Series radio broadcast. (New York Giants vs. Yankees.)
1922-52: The "golden age" of radio. Among the greats: Jack Benny, George Burns and Gracie Allen, Eddie Cantor, Bob Hope, Bing Crosby. "Amos 'n' Andy," with Freeman Gosden and Charles Correll, brings America to a standstill for its broadcasts in the 1930s.
Nov. 15, 1926: The National Broadcasting Company, the first radio network, begins.
1927: Federal Radio Commission formed, precursor to the Federal Communications Commission.
1928: William Paley buys a chain of 16 stations that become the Columbia Broadcasting System.
1935: First demonstration of FM radio.
October 30, 1938: Orson Welles's famous radio dramatization of H. G. Wells's "The War of the Worlds" sends the nation into a panic.
1939-45: Wartime news broadcasts increase the importance of radio as a source of information.
1943: The American Broadcasting Company is formed.
Early 1950s. As radio performers desert to television, radio's golden age ends. Cleveland deejay Alan Freed begins to introduce millions of young radio listeners to rock-and-roll music.
1961: All-News Radio format begins on XTRA, a Tijuana, Mexico, station that aims English-language programs at southern California.
1964: Many stations begin all-talk and call-in shows.
1970: National Public Radio established as a private, nonprofit corporation.
1987: WFAN in New York becomes the first 24-hour sports station.
1995: Some 11,500 radio stations are heard on more than 500 million radios in the United States.