The first are the World dungeons which are for those that enjoy an Epic adventure. World dungeons are set up for a hardy adventure. Group or guild raids would be more common within these areas. Thanks to the Instanced zone it will help keep "Farming" down.
Micro dungeons are the second installment of the two types and they consist of small to extremely large environments. It's "Seamless" in transition says blizzard. They consist of Haunted Mines, Caverns, Sunken ships and so much more!
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Is that a giant diaper?