Alfheim

The Home of the Elves and Land of the Fae, a mercurial realm, inscrutable and unknowable. Its topography is strange and seems to rotate around Elven communities or communities of other beings; stability in the face of wildness. Indeed it is the wildness of the natural terrain; deep impenetrable forests, twisting, disturbed marshes, and turbulent,rock-filled waters that define most of Alfheim. In most regards, it is basically the Feywild(as outlined on page 50 of the DMG). Those who leave Alfheim and are not Elves or Fey must succeed on a DC10 Wisdom save or lose their memories of their time in the realm. Even those who succeed will find their memories somewhat hazy. Time is also distorted(consult the charge on pg. 50 of the DMG).

Geography

Deep impenetrable forests, twisting, disturbed marshes, and turbulent,rock-filled waters