My personal favourite composer as many of you would know is Mahler, because the melodies are brilliant, and the orchestration really brilliant.
Therefore the first symphony I will look at is Mahler's Symphony No. 6, in A minor. The 'Tragic'
It is easily the most structured of the Mahler symphonies and has the traditional 4 movements. It is a work of titanic proportions, and requires a mammoth orchestra to perform. All four movements are brilliant, with a furious opening, a diabolical scherzo, a beautiful andante and a fiery finale. Unlike all other Mahler symphonies, and the radiant dying moments, this ends in a minor key, with a sudden crash. Brilliant orchestration is evident throughout, and I have never heard themes
Although it is such a negative work, Mahler wrote it while going through the best times of his life.
My favourite recording of this work is the controlled Boulez, Vienna Philharmonic recording.