Katie Derham continues Radio 3's month of programmes complementing the BBC4 series "Symphony" - including every note of every Symphony featured in the television series. This week the Afternoon on 3 series reaches the twentieth century and find the Symphony flourishing far from its Austro-German foundations. Today's programme begins with a live concert from BBC Hoddinott Hall, Cardiff: Pascal Rophé conducts the BBC National Orchestra of Wales in music by two of the greatest symphonists of the century, from Finland and Russia: Sibelius and Shostakovich - including both Sibelius's famous Valse triste and his last surviving Symphony, the Seventh, in which he quotes the Valse triste. Sibelius may have completed an Eighth Symphony, but if he did, he seems to have destroyed it. And today Katie follows the Sibelius with the last completed Symphony by another twentieth-century giant of the genre (and who also greatly influenced Shostakovich): Gustav Mahler.