Every radio station has a government mandated station identification - a host is required to announce a station's call letters every hour, on the hour. Here's a look back at some of the most unique station IDs from the past 90 years.
This station ID is from November 25, 1936.
Change came in 1938. With the storm of World War II less than a year-and-a-half away, the fascist governments of Italy and Germany were bombarding resource rich South American countries with shortwave radio broadcasts with the hope of gaining new allies. Mayor La Guardia and then Station Director Morris Novik decided to counter this propaganda. On May 27, 1938, WNYC initiated a series of half-hour programs extending 'good will greetings' to South America through General Electric's shortwave station (W3XAF) in Schenectady, New York. Each program ended with this statement:
"This program comes from WNYC, New York City's own station, where seven-and-a-half million people, who have come from all parts of the world, are now living in peace and enjoying the benefits of democracy."
Soon after it was slightly modified and adopted as WNYC's regular station identification as heard in this February 22, 1941 clip.
Following the Japanese attack on Pearl Harbor in December, 1941, the phrase "in peace" was dropped.  It remained absent until the end of World War II. Sometime after the war the station ID was reworked to include the chimes hourly from the clock at New York City Hall. It sounded like this through much of the 1950s:
It is interesting to note, however, that as a consequence of WNYC's effort to respond to fascist broadcasts, it decided to set up its own shortwave station W2XVP, operating with 1,000 watts of power at frequency of 26.1 megacycles. The original idea was to broadcast programs in Spanish or Portuguese to South America. Broadcasting magazine announced the "high fidelity" transmitter's testing by Chief Engineer Isaac Brimberg in their March 1, 1940 edition saying, the unit was built by New York's Radio Receptor Company. But it appears that by January, 1941 the notion of WNYC successfully countering the shortwave punch of the Axis powers was a bit over-extended. The facility instead went on the air for a couple hours a day following WNYC-AM's regular sign-off at sundown, repeating the classical music program The Masterwork Hour, along with other selected music, news and commentary.
These shortwave broadcasts continued for about a year before the transmitter was dismantled and efforts to get a frequency modulation facility up and running were well under way. WNYC-FM went into regular service in March, 1943 as W39NY.
 According to the October/November, 1939 WNYC Masterwork Bulletin, WNYC was also sending programs to the international shortwave station WIXAL in Boston, (later WRUL).
 The New York Journal American, May 26, 1938.
 Associated Press report, December 13, 1941.
 The February 1, 1940 edition of Broadcasting noted that WNYC had begun using the City Hall chimes for its "noonday time signal."
 A History of WNYC, unpublished drafts of 1940 WPA manuscript, New York City Municipal Archives microfilm.
 Broadcasting, March 1, 1940, pg. 63. Note: The news brief incorrectly indicates the station call letters as W2RVP.
 "WNYC on Shortwave," The New York Sun, January 4, 1941. p. 20.