Thousands of people flooded downtown Palo Alto Sunday evening to hear dozens of bands and individual musicians bring the world of music to street corners and public plazas.

The event was the first "World Music Day" and the throngs -- no one has a precise count or even a good guess at how many showed up -- strolled up and down University Avenue and side streets.

Some danced to livelier music, while others listened to the disparate offerings of the virtually impromptu event.

The range of music was vast, from harmony quartets and groups to harp-and-flute music, Celtic singers, Latin pop rock and blues, folk, Greek, Chinese, Irish, Scottish, hip-hop and even Tasmanian tunes. Balkan, Klezmer, "ragpop," classical, jazz and "postmodern noise and avant-garde music" all drew clusters of listeners in the balmy, perfect-temperature 5 to 8 p.m. evening.

Strollers and sometimes bemused motorists threaded their way from street to street while the music played. People stopped to chat with friends and acquaintances, and asked each other how they liked the event. Restaurants, many with doors open wide to let in the music and customers, were jammed.

There were no sound stages on the street corners, and the bands were unpaid, except for contributions dropped in instrument cases, hats or containers. Most were acoustical or used their own small amplifiers. They were positioned strategically so the groups' music did not conflict with the playing of other groups.

One attendee told volunteer Jack Hamilton, who was taking a survey, that she thought it would be great if University could be closed for next year's repeat -- a widespread assumption.

The event was the brainchild of Claude Ezran, a member of the city's Human Relations Commission and a former candidate for Palo Alto Board of Education, who said this type of event originated in France in 1982 and has spread throughout Europe.

Ezran, exuberant after the success of the event, said he first saw it work in London, and thought it would be a natural for Palo Alto.

As for closing University to auto traffic next year, Ezran said that would need to be looked at and businesses would need to be consulted. At a post-event gathering at Ezran's home on Louis Road, several musicians said closure would be nice but the event seemed to work fine without it.

An earlier "Promenade" event in which University was closed for a full day to allow for construction of stages and sound set-ups, generated strong protests and made city officials gunshy of additional closures.

But the no-stages nature of the World Music Day would mean rerouting through traffic to Hamilton or Lytton avenues for only a few hours, supporters of the idea said.