HAVANA, March 29 — It was in the air: the thrill of the illicit and the new, the excitement of discovery and the charge of an encounter with idols. And it didn’t take place on a baseball field.

Just after the Baltimore Orioles broke ground by playing a Cuban team here, musicians by the score and fans by the thousands poured into the Karl Marx Theater on Sunday night in this city’s elegant Playa district for the Music Bridges concert, the biggest convergence of foreign and Cuban musicians since the revolution. Before that came a week of impromptu collaborations out doors and in makeshift studios.

From the United States came singers like Bonnie Raitt, Jimmy Buffett, Beth Nielsen Chapman, Joan Osborne, Lisa Loeb, Burt Bacharach and more. The Cubans brought together musicians from the folk, rock, and popular dance music scenes. In the end the all-star concert at the Karl Marx had people dancing and cheering, and the future of this enterprise, musical or otherwise, seemed as hazy and unpredictable as anything else involving Cuban-American relations.

Music Bridges, an organization that specializes in concerts in politically sensitive countries, had spent a year and a half pulling together the legal and practical permission from the United States and Cuba.

Music Bridges, with its 40-some participating American musicians, had came to Havana and taken more than 120 rooms in the Hotel Nacional, overlooking the ocean. The organization filled the sixth-floor executive offices and the presidential suite, along with three rooms that had been converted into recording studios. For a week Cuban and American musicians were to collaborate on songs and to present the works on the final night in a long concert at the Karl Marx Theater.

At events around the city American musicians were getting a feel for the power of Cuban music and its bacchanalian spirit. In the wee hours of Thursday night at La Cecilia nightclub, Michael Franti, a rapper and band leader from San Francisco, mounted the stage with Cuba’s version of the Roilling Stones, Los Van Van, a 30-year-old institution playing hard-rocking dance music.

Mr. Franti started rapping and repeating a phrase, and Pedrito, one of the group’s singers, entered the fray; the two swapped nonsense syllables, but with rhythm. It would have brought down the roof, but La Cecilia is outdoors. Members of the audience — made up of faranduleros, the habitués of Havana’s nightlife scene, Music Bridges staff members and performers, and journalists — were impressed and they danced.

On Saturday at the Charlie Chaplin Theater in the Vedado district, Americans and what remains of members of Cuba’s intellectual culture had the chance to hear the Buena Vista Social Club play cha-cha-chas, mambos and boleros that have mostly fallen into disregard. The performance, which was not part of Music Bridges, offered an opportunity to hear music with extreme grace and humor, one of the great musical syntheses of the New World, where classical, jazz and African music merged into something special.

MusicBridges.com : Uniting People and Cultures around the world through music

Music Bridges is dedicated to the creation and development of international collaborative music projects and related special events to serve as a cultural link between nations and foster greater understanding among the worldwide human community.