When Audioslave took the stage May 6 at Havana's outdoor Anti-Imperialist Tribunal to play a free show, guitarist Tom Morello admits he didn't know what to expect. "We had no idea if it was going to b

When Audioslave took the stage May 6 at Havana's outdoor Anti-Imperialist Tribunal to play a free show, guitarist Tom Morello admits he didn't know what to expect.

"We had no idea if it was going to be 70 people or 70,000," he tells Billboard. It turns out it was the latter -- many of whom were clearly fans of the band. "A lot of them were singing along, some were making a mosh pit, some were salsaing, some were pogoing. A lot of them just couldn't believe it was really happening."

Despite U.S. restrictions on travel to Cuba, a number of American artists have played there. However, Audioslave is believed to be the first rock band to perform an outdoor show in the country. The show and the band's adventures in Cuba were recorded for a future DVD release.

The trip was organized by the U.S. government and the Instituto Cubano de la Musica and included meetings for the band with music students and Cuban musicians. "It was astonishing," Morello says. "Around every corner there were great musicians."

Despite the obvious tie-in with the band's May 24 Interscope/Epic release, "Out of Exile," Morello stresses playing Cuba had nothing to do with the project's title. "We're not that clever," he says. "We made overtures years ago, when we were in Rage Against the Machine, and for one reason or another had been unable to get it done. It was a fulfillment of a dream."

There were reams of red tape to push through on both the American and Cuban side -- so much that Morello says the band didn't get the final OK until 36 hours before it was set to leave.

Two weeks before the trip, the group had a surreal conference call with representatives from all sides. "It was this incredible conversation," Morello says. "It was, 'You may not go here. You may not talk about this. The rooms are going to be tapped.' And it couldn't have been less like that. Everyone was so gracious and warm."

After surviving all the bureaucracy, Morello says, "we walked out onstage and our drum monitors weren't working, and we were like, 'After all this, we're not going to be able to play?' But we just took a lesson from some of the street musicians we met there and just improvised and just rocked it until they could fix them."