Although open to criticism that it merely glosses over various corners of the world, the film is unquestionably devoted above all to music-making and how it functions to bind together disparate groups. Harkaitz Martinez and Igor Otxoa, playing an ancient and remarkably simple Basque instrument called the txalaparta (made of two or more wood planks placed on a stand and covered with insulated material, and played with thick sticks), produce just the kind of drum-based music that allows them maximum flexibility to blend in with a rainbow of world music traditions.

Brief, typically pulsing opening shows the pair sawing and sanding the wooden elements of their latest txalaparta with Otxoa likening the music's improvisation to travel: "You don't know where it will end up."

First stop: Mumbai, where the guys practice and then perform with Jayan Nair and his high-energy ensemble. Soon, they venture by muddy backroads into the state of Gujarat to meet the Adivasi people, nomads cut off from India's dominant caste system. After a goat sacrifice, musician Bagubahi plays a song about a quest for the earth's sounds, using an even more primitive instrument than the txalaparta.

Martinez and Otxoa travel by cross-country skiing into the Arctic Circle for some rewarding performances on a txalaparta carved purely from ice, producing an astoundingly echo-y acoustic effect. They also find some gorgeous voices to play against, including that of vocalist Jana Mangi, recorded in a giant igloo.

Director Raul de la Fuente makes all this even more exotic than a description suggests, and (as his own editor) finds an angular, elliptical cutting style -- sometimes recalling Michael Winterbottom's approach in "In This World" -- that communicates his own giddy excitement at being able to jump from one extreme corner of the globe to another.

He next leaps from ice to desert, as Oreka Tx seeks and finds a wide range of musical partners in the greater Sahara stretching from Morocco to Algeria -- from a wandering group of Sudanese musician/dancers to several Berber master players, including Ichou Benazza. After chiseling a txalaparta out of rock, the duo performs to a rapturous crowd in an Algerian refugee settlement, Camp Dalja, where Berbers have fled from the country's bloody civil war.

Final section follows the happy wanderers through the vast steppes of Upper Mongolia to a snowbound area occupied by the Tsaatan, a tribe so tiny that only 40 families remain. Finale montage, matching the txalaparta's heavily syncopated rhythms with the beat of galloping horses, finishes pic on an exceptional high.

Only the best homevid audio playback systems are suitable for capturing the inevitable vid version of pic's complex and superbly mixed soundtrack; audiophiles aside, pic is best suited for viewing in a cinema with a solid Dolby Digital system. De la Fuente's lensing balances a rough cinema-verite approach with a grand eye for landscapes.

Camera (Technicolor, widescreen), de la Fuente; editor, de la Fuente; music, Oreka Tx; music supervisor, San Vicente; sound (Dolby Digital), de la Fuente; supervising sound editor, Ernesto Santana; supervising sound mixer, Alfonso Pino; assistant director, Inigo Ganzarain. Reviewed at Guadalajara Film Festival, March 26, 2007. (Also in San Sebastian Film Festival, Intl. Documentary Film Festival Amsterdam.) Running time: 86 MIN.