Wagner said that Wotan had ended up by willing his own destruction. Wotan
loses part of himself, a part that continues to live in his daughter
Brünnhilde. She learns, and teaches Wotan, that love wins over power, in
the end. Not only is Valhall destroyed, but the Earth is purified by fire
and water. Perhaps Valhall burns for the same reason Manderly burns in
'Rebecca' and Atlanta burns in 'Gone with the Wind': to symbolize the end
of the old and the beginning of the new.