Edgard Varèse's Amériques is one of modernism's greatest enormities. Completed in 1921, it's ostensibly a massive cacophonic portrait of New York, the French-born composer's home from 1915. Like many early 20th-century avant-gardists, however, Varèse saw the US as an icon of almost limitless potential. Amériques also carries connotations of the need for the creation of a new musical language in order to depict a new world.

Its outings are rare. It requires vast forces, the orchestral writing is exacting, and some conductors simply shun the piece. James Conlon's performance with the BBC Symphony Orchestra was consequently brave as well as formidable. Conlon's hard-driven style can sometimes seem unyielding, though it's admirably suited to Varèse. The great swathes of sound erupted with brutal clarity. The brief passages of stillness, in which we heard meditative woodwind or echoes of distant jazz, afforded little respite from the power. Startling though it is, the score is not without its European antecedents: Conlon also brought home its reliance on Straussian orchestral enormity and Stravinskyesque rhythmic propulsion.

Its companion pieces consisted of another cityscape, in the form of Britten's Les Illuminations, and two great depictions of the sea. Like Amériques, Les Illuminations was written in New York, though the city in question is Paris, refracted through the poetry of Arthur Rimbaud, set for tenor and strings. John Mark Ainsley was our guide through the "savage parade" of urban existence in a glorious performance riddled with irony, eroticism and near obscenity. The Sea Interludes from Britten's Peter Grimes and Debussy's La Mer formed the seascapes. The latter suffered occasionally from Conlon's over-emphatic style, leading to a couple of inappropriately blowsy climaxes. The Interludes from Grimes, however, were phenomenally done - heaving with menace and reminding us throughout that in the world of Britten's opera the sea is a metaphysical force that shapes the characters' lives with tragic force.