Minecraft adventure map not loading?

I downloaded the map Witchcraft and Wizardry and also managed to add it to my worlds, but every time I want to play it only loads my arm and the rest remains black.

What could that be?

Will the rest of the time remain black or will your Minecraft just crash after a while?

If this doesn't sound to me as if the map were damaged or you are below the map then everything is always black, if possible go to the Spectator or Creative mode and have a look.