"The Wastelands are like the center of Creation itself. They are constantly shifting and changing. What you see and experience one day may be completely different from another. There is no true matter here, no substance. You may hear or feel things that do not make sense, and those who are not prepared may become lost forever. Imagine being cast into the depths of the ocean, down where no light can penatrate, tossed about by the movements of the water. It is a dangerous and frequently misunderstood place, even by the angels."— Tyrael(src)
The Wastelands are a murky world located on the edge of Pandemonium. They are constantly in flux, and are without true form. Those who enter the Wastelands can find themelves feeling disorientated and under emotional assault, and can find themselves lost in the realm.