This is my favorite poem: Der Panther / The Panther by Rainer Maria Rilke.
It´s about a captivated panther he saw at a Menagerie and it´s existence in the cage.
I always wished to release him....
Jardin des Plantes, Paris 1903
The Panther
His gaze, from pacing behind the bars that hold him,
became worn out, it can take in nothing more,
it seems to him as if there were a thousand bars before him,
and beyond these thousand bars, no world.
The soft footfalls, the smooth muscular canter,
that goes around in ever smaller turns,
is like a dance of strength around a center,
in which, like dazed, a greater spirit burns.
Only at times the curtains of his sensing,
lifts mutely up - an image enters in,
passes through the body´s silent tension,
reaches the heart and dies within.