The 50th anniversary of John Lennon's birth was observed with a global celebration Tuesday as his peace anthem "Imagine" was played for an estimated 1 billion people in 130 nations.

The song was played shortly after 10 a.m. following a brief ceremony at the United Nations that featured the ex-Beatle's widow, Yoko Ono. Marcela Perez de Cuellar, wife of the U.N. secretary general, also provided a brief introduction. A recorded message from the slain Beatle was played as well.More than 1,000 radio stations and networks from 50 countries had signed on for their satellite broadcast by last week. U.S. Armed Forces television and radio beamed the event to 80-plus countries. MTV was to broadcast the program in 25 countries.