Maradaun to me is just an amazing instance.
Orange entrance: A cavern with walls that breath, and plantlife out to get you.
Purple entrance: A cavern that is the stronghold of demons.
Either way, you have to fight in the deep dark caverns and bowels of Kalimdor. Then without warning, the sky opens up above you, plants are green again, there is a warmth and beauty in your surroundings, which is in stark contrast to the grey, cold lands of desolace. An oasis waiting to be conquored in the middle of the dieing, drab, dreary, dry, desolate lands that surrounds you.
How can you not love Maraudon?