The poem discusses W.H. Auden's poem "Musée des Beaux Arts" about Pieter Bruegel's painting "The Fall of Icarus".
1) The poem is named after the museum in Brussels that houses Bruegel's painting, which depicts Icarus falling into the sea after his wings melt, in the background of an otherwise ordinary landscape.
2) The central theme is how humans view individual suffering with apathy, as life goes on around "disasters" like Icarus's death.
3) Auden visited the museum in 1938 and was inspired by Bruegel's painting to write this poem focusing on the indifference with which the painting depicts I