The Depression is a hellish space. It is a big concavity in the sea of sand, fortified by layers of gypsum rather than rock from being completely levelled. The lowest point of the pan reaches 200 metres below the sand level. There, temperatures are lethal, reaching 70-80 degrees centigrade with regularity. Most of human equipment cannot withstand such temperatures long, progressing quickly from deformation to malfunction. Unprotected humans die rather quickly, stillsuits increase the odds of survival, but just.

Worms reign there. Storms are born there. Equatorial belt notwithstanding, this is as bad as Arrakis can be.

The only creatures known to cross this space, apart from sandworms, are bats, and only at night.