The Alchemy of Sorrow
One man lights you with his ardor,
Another puts you in mourning, Nature!
That which says to one: sepulcher!
Says to another: life! glory!
You have always frightened me,
Hermes the unknown, you who help me.
You make me the peer of Midas,
The saddest of all alchemists;
Through you I change gold to iron
And make of paradise a hell;
In the winding sheet of the clouds
I discover a beloved corpse,
And on the celestial shores
I build massive sarcophagi.
- Charles Baudelaire 1961, trans. William Aggeler, 1954
The topic of Baudelaire's great poem should be clear enough--transformative sorrow. However, I don't feel that this does the poem justice. So: read it a few times! This will be helpful with any poem. It can take a while to read it enough so that it rings clearly. Some poems teach patience and receptivity. I've been thinking of this often recently: the difference between a poem and a philosopical work. Both can be precise, have ideas etc, but the difference in form has an effect. For me, poetry helps defend against totally dogmatic thought, and against the pride of knowing things too quickly. Having an explanation does not mean knowing the thing! And a poem can reveal this!
As I hope that Baudelaire's does. It is a beautiful poem. A tip that may help sort out the poem: "Nature," in the second line, refers to man's own nature, I believe. It seems that there is a macrocosm/microcosm work here. In other words, Nature is internal and external. This may make sense of the final stanza, for if this is the case, the reader builds the sarcophagus internally, and the celestial shores are in his heart.
I recommend reading more Baudelaire; he's moving and insightful about existential anxiety, relational anxiety, relationship decay and more.