There is a section of the border wall between Southern California and Northern Mexico that is covered in crosses, hundreds of them, white and made by hand, tacked onto sheets of industrial metal. The crosses are on the Mexican side, and they’ve been put on the border wall to keep the dead alive at the very place they vanished, memorials for migrants who crossed into a world that wasn’t the north, white traces on rusty steel of lives that are no longer.

When the Catalan singer-songwriter Pau Dones, leader of the Barcelona band Jarabe de Palo, saw the white crosses of Tijuana, he didn’t think of Mexico or the US. He thought of home, of the watery Strait of Gibraltar, the border between southern Spain and northern Africa that also takes lives, but where there are no crosses to commemorate the dead.

Spain is a country deeply protective, and deeply forgetful, of its own African, Arabic, and Gypsy histories. You can ride the metro in Madrid — a system built on interconnections and shoulder-to-shoulder commingling — and still find graffiti that reads, "Spain for the Spanish. Out with the Third World." On a recent Saturday in the city’s Plaza de Santa Ana, cafés overflowed with light-skinned Spaniards sipping beer and bubbling water next to a statue of the Andalusian poet and champion of dark Spain Federico García Lorca. Above his name, someone had spray-painted the word "disobedience."

Dones may look white too, but he uses Jarabe de Palo’s music to voice his own "disobedience" toward Spanish cultural chauvinism. For the band’s fourth and latest album, Bonito (WEA International), he has written "Las cruces de Tijuana," a song that pays tribute to Tijuana’s white crosses while wishing that the Spanish border cities of Gibraltar and Ceuta exhibited memories of their own. "The crosses I saw in Tijuana," Dones sings over Mexican son juasteco guitars that blend into norteño accordions and banda brass, "made me remember the crosses that nobody has put between Ceuta and Gibraltar."

Dones isn’t the first child of Barcelona who’s used Tijuana to comment on Spain’s own cultural violence against immigrant Arabs, Africans, and Gypsies. Manu Chao did it back on his 1998 release Clandestino (Ark 21), which turned Tijuana, Ceuta, and Gibraltar into transcontinental sister cities connecting nodes on an imaginary musical map where people traveled across borders as free, and as invisibly, as the wind. Chao remains the unofficial godfather of the current Barcelona scene, where in the past few years, anti-colonial lyrics, Spanish/French/Arabic trilingualism, and First-World-meets-Third-World sound clashes have become a trademark.

The Catalonian capital has been dubbed "Bastard Barcelona" on the new compilation Barcelona Zona Bastarda (Delanuca). The white pages of the Barcelona phone book (with its catalogue of polyglot, multinational last names) come stamped on the compilation’s two CDs, and there is hardly a national style not represented here. Bands like Macaco, Dusminguet, La Carrau, and El Payo Malo mash up cumbia and rai, ska and hip-hop, punk and samba, folk and techno — everything gets mixed together when cultures mix. As the liner notes spell out, this is "the other Barcelona," the "mestiza Barcelona" of squatters, immigrants, and ghettos that tourist maps render invisible.

Besides Dones, Barcelona has as one of its most important new voices the band Ojos de Brujo, who turn to the Spanish musical past to figure out how better to live in the Barcelona present. Their latest CD, Bari (Fábrica de Colores/Satellite K), cuts up flamenco and rumba catalana guitars with turntable scratches and christens the style "jiphop flamenquillo" — ancient music that speaks to the urban realities of today. Instead of looking over to Tijuana, like Dones, they look straight at Barcelona, and they see streets that still hum with traditional soleás, bulerías, and siguiriyas. "Bulería del Ay" even uses a classic flamenco form to lament a love lost on the Internet, an e-mail that never received a reply.

Ojos de Brujo rework their own past as well. "Tahita," a staccato fret-thumped hip-hop freestyle from their last album, gets remixed over waves of electronic beats on Bari. Its raspy chant of a refrain — "abriendo puertas" ("opening doors") — repeats over and over, as much a description of what they’re doing as a depiction of what needs to be done. It’s the very thing Dones went all the way to Tijuana to imagine: the power of opening doors to an outside that is already within.